Former eastern branch of the Nile discovered in Egypt.

From the End of the Pleistocene to about 5000 years ago, much of the Sahara is thought to have been covered by a lush green savannah, with numerous, now dry, lakes and rivers, providing a home to large Human and Animal populations. During this time the Nile was a much more substantial waterway, wider and deeper than it is today, prone to major flood events, and surrounded by extensive marshes and wetlands, making the Nile Valley a difficult environment for the hunter-gatherers of the period, and it appears to have been largely uninhabited. 

From around 5500 years ago the climate of the Sahara began to dry out, with the lush grasslands that had covered much of the area slowly disappearing, while the Nile Valley became a habitable refugia, attracting people to settle in the area, settle and begin farming. This environment enabled a great cultural flourishing, and eventually the formation of one of the word's first centralized states, the Old Kingdom of Egypt, which formed around 2686 BC. The Old Kingdom quickly established a culture of monumental agriculture, which most notably manifested as the great pyramids of the period. 

At this time the discharge of the Nile was still much higher than it is today, and multiple branches of the river are thought to have been present at any time, meandering across the floodplains of Sudan and Egypt. Since this time the Nile Valley in Egypt has undergone significant changes, due to the decline in water flow over the past four-and-a-half millennia, and the building of the Aswan High Dam in the 1960s, which made the Nile Valley in Egypt a much more controlled and predictable environment.

To the Ancient Egyptians the Nile was a vital resource, providing regular floods which kept the fields irrigated and fertile, and a ready-made transport network which enabled them to move food, manufactured goods, and building materials, to wherever they were needed. However, they had much less control of this resource than modern Egyptians, and it was prone to migrating laterally across the desert, leaving settlements and building projects cut off from water resources and easy transport. The location of many ancient sites, far from the current course of the river, provides a testament to the movement of the river, but the exact course of the river in ancient times is less clear, difficult to map due to modern farms and settlements covering the floodplain. Thus, we remain uncertain where the ancient courses of the river ran, nor if more than one branch was active at any given time. 

The pyramids and great temples of the Old Kingdom, which logically would have been constructed close to a navigable waterway, area arranged in a roughly linear pattern, running parallel to the Nile from Lisht in the south to Giza in the north.

In a paper published in the journal Communications Earth and Environment on 16 May 2024, Eman Ghoneim of the Department of Earth and Ocean Sciences at the University of North Carolina Wilmington, Timothy Ralph of the School of Natural Sciences at Macquarie University, Suzanne Onstine of the Department of History at  the University of Memphis, Raghda El-Behaedi of Near Eastern Languages and Civilizations at the University of Chicago, Gad El-Qady of the Egyptian National Research Institute of Astronomy and Geophysics, Amr Fahil of the Geology Department at Tanta University, Mahfooz Hafez, Magdy Atya, Mohamed Ebrahim, and Ashraf Khozym, also of the Egyptian National Research Institute of Astronomy and Geophysics, and Mohamed Fathy, also of the Geology Department at Tanta University, present the results of a study which used remote sensing, geomorphological, soil coring and geophysical evidence to map the Western Desert between Lisht and Giza, demonstrating the presence of a lost river branch running along this course. 

Ghoneim et al. used Synthetic Aperture Radar to create a three dimensional map of the Nile Floodplain and the surrounding desert, finding evidence of a former river channel between Lisht and Giza, which would have been navigable during the Old Kingdom, and until the Second Intermediate Period, passing by 31 pyramids from the Third to Thirteenth Dynasties. They name this the Ahramat Branch, from the Arabic 'al'ahramat' (الأهرامات), meaning 'pyramids'. This branch is largely covered by fields on the modern Nile Floodplain, making it invisible in visual satellite images, but can be traced on the ground surface by TanDEM-X satellite radar imagary and Topographic Position Index functions on Geographical Information Systems  software. This channel lies between 2.5 and 10.25 km to the west of the modern course of the Nile River. This channel appears to have been about 64 km in length, between 200 and 700 km wide, and between two and eight metres deep. The size of this waterway, combined with its course directly past the pyramids and other works of monumental architecture now marooned in the desert, implies that it was of great functional importance to the early Ancient Egyptians.

The water course of the ancient Ahramat Branch. (a) Shows the Ahramat Branch borders a large number of pyramids dating from the Old Kingdom to the 2nd Intermediate Period and spanning between Dynasties 3 and 13. (b) Shows Bahr el-Libeini Canal and remnant of abandoned channel visible in a 1911 historical map (Egyptian Survey Department scale 1:50,000). (c) Bahr el-Libeini Canal and the abandoned channel are overlain on satellite basemap. Bahr el-Libeini is possibly the last remnant of the Ahramat Branch before it migrated eastward. (d) A visible segment of the Ahramat Branch in TanDEM-X satellite radar imagary is now partially occupied by the modern Bahr el-Libeini Canal. (e)  A major segment of the Ahramat Branch, approximately 20 km long and 0.5 km wide, can be traced in the floodplain along the Western Desert Plateau south of the town of Jirza. Location of (e) is marked in white a box in (a). Ghoneim et al. (2024).

A survey carried out using Ground Penetrating Radar and Electromagnetic Tomography found a former river channel was buried beneath 1-1.5 m of modern cultivated sediment, which matched the position of the channel observed in the satellite radar imagery. The sediments within this channel are different to both the overlying silt deposits of the modern floodplain and the sandy sediments on either side of the channel. At the site where the ground survey was carried out, the riverbed sediments were approximately 400 m wide and 25 m deep (the depth of riverbed sediments implies the presence of a river for a long period of time, rather than relating to the depth of the river).

Two sediment cores were taken in this area. The first of these, Core A, was taken between the centre of the channel and the left bank, and reached a depth of 13 m. This core had an upper layer of sandy brown mud which reached down to about 2.7 m. Beneath this was a layer containing limestone and chert fragments, a reddish sandy mud layer with gravel and handmade material inclusions, then from about 3 m to about 5.8 m, another reddish sandy mud layer with gravel and Freshwater Mussel shells, followed by another layer of limestone and chert fragments, a reddish sandy mud layer with gravel and handmade material inclusions, then a black sandy mud from 6 m to 6.8 m, which graded into a well sorted medium sand; this was clean of mud by about 8 m, and persisted till about 13 m. The second core, Core B, was taken on the right bank of the branch, and reached a depth of 20 m. Here, recent brown sandy muds reached a depth of 1.5, beneath which alternating brown and gray layers of silty and sandy mud down to about 4 m. This was followed by a black sandy mud layer from 4 m to 4.9 m, then another reddish sandy mud layer with gravel and freshwater mussel shells till about 5 m. From 5 m to 20 m the profile was dominated by a clean, well sorted, medium sand. In both cores the sand layers contained groundwater, suggesting that the former Ahramat Branch of the Nile still serves as a conduit for subsurface water flow within the Nile Floodplain.

Deep sediment cores from the southern segment of the Ahramat Branch. It shows two-soil cores, core A and core B, with soil profile descriptions, graphic core logs, sediment grain size charts, and example photographs. Ghoneim et al. (2024).

The pyramids of Ancient Egypt were not isolated buildings. Each formed part of a temple complex, which also included a mortuary temple, which stood next to the pyramid, and a valley temple, beside the waterway and some distance from the pyramid and mortuary temple. All of these were connected by causeway (raised walkway), which provided a path to the pyramid complex. Many of the causeways associated with pyramids on the Ahramat Branch have causeways arranged at right angles to the course of the waterway, and end where the riverbank would have been.

The valley temples of Ancient Egyptian pyramid complexes served as disembarkation points for visitors arriving by river. Many of these valley temples have never been found, and are presumed either to have been totally plundered for their stone or to be buried beneath the desert sands or agricultural lands of the modern Nile Valley. Five valley temples are still at least partially present on the Ahramat Branch. These are associated with the Fourth Dynasty Bent Pyramid, Pyramid of Khafre, and Pyramid of Menkaure, the Fifth Dynasty Pyramid of Sahure, and the Sixth Dynasty Pyramid of Pepi II, all of which date from the Old Kingdom. All of these valley temples are adjacent to the Ahramat Branch waterway, indicating that this branch of the Nile was a navigable waterway during the Old Kingdom.

Ghoneim et al. use the positions of the pyramids arranged along the Ahramat Branch to reconstruct a history of the waterway. They conclude that the waters of were highest during the Fourth Dynasty, with pyramids from this time placed on high elevations far from the waterway. The water appears to have been much lower during the Fifth Dynasty, with pyramids consequently placed at much lower elevations, closer to the floodplain. The waters appear to have begun to rise again during the reign of Unas, the last Pharaoh of the Fifth Dynasty, and to have continued to rise during the Sixth Dynasty, with the pyramids of Pepi II and Merenre located deep into the desert.

The pyramid of the Eighth Dynasty Qakare Ibi is again located low and close to the riverbed, suggesting that waters had again fallen by this time. Qakare Ibi lived during the First Intermediate Period, after the fall of the Old Kingdom, which is known to have been associated with a significant drought, during which the annual flood on the Nile failed to appear for between 30 and 40 years. Sediment cores takin in Memphis, the capital of the Old Kingdom, have shown the city to have been covered by about 3 m of windblown sands. The Ahramat Branch seems to have shifted significantly to the east during the First Intermediate Period, then continued to drift eastwards during the Middle Kingdom, before effectively drying up during the Second Intermediate Period.

Sentinal 1 radar images show a number of apparent channels running from the Western Desert Plateau to the Ahramat Branch, suggesting tributaries to the river. All of these are now covered by sand, and therefore invisible in spectrographic images, but appear dark in the radar images, suggesting fluvial sediments beneath thr surface. Notably, the Sentinal 1 radar system, which can penetrate about 50 cm of dry sediment, is incapable of seeing the main path of the Ahramat Branch, which is largely covered by floodplain farmland. The inlets were visible in TanDEM-X satellite radar imagary, which suggested an extensive network of waterways in this area.

Using Radar and the Topographic Position Index for mapping major channels (inlets) connected to the Ahramat Branch. (a) Conceptual sketch of the dependence of surface roughness on the sensor wavelength λ. (b) Expected backscatter characteristics in sandy desert areas with buried dry riverbeds. (c) Dry channels/inlets masked by desert sand in the Dahshur area. (d) The channels’ courses were extracted using Topographic Position Index. Negative Topographic Position Index values highlight the courses of the channels while positive Topographic Position Index signify their banks. Ghoneim et al. (2024).

Several pyramids from the Fourth and Sixth dynasties appear to have causeways that connect to these inlets, rather than the main Ahramat Branch waterway.  Thes include the Bent Pyramid in the royal necropolis of Dahshur, the first of three pyramids built by Sneferu, the first Pharaoh of the Fourth Dynasty, and one of the largest and oldest pre-Giza pyramids. The location of this pyramid has long been a mystery, as it is deep within the Eastern Desert, far from the modern Nile Floodplain. The Bent Pyramid has an impressive 700 m limestone block causeway, connecting it to a valley temple, which until now has been mysteriously distant from any body of water, facing onto the dry Wadi al-Taflah. Ghoneim et al.'s reconstruction places the causeway on an inlet of the Ahramat Branch, which they name the Dahshur Inlet, and which would itself have been more than 200 m wide. Ghoneim et al. reason that this inlet would still have been flooded during the reign of Sneferu, and that it would have played a major role in the movement of the materials used to construct the temple complex. The inlet could also have been used to move materials for the construction of the Red Pyramid (Sneferu's second), which is also in the Dashur area, although no trace of a causeway or valley temple associated with this pyramid remain. Several Middle Kingdom pyramids are also found in this area, including the Black Pyramid of Amenemhat III, the White Pyramid of Amenemhat II, and the Pyramid of Senusret III, although these are all at least a kilometre to the east of the Old Kingdom pyramids, lending support to the idea that the Ahramat Branch migrated eastward over time.

The Sakkara and Dahshur inlets are connected to the Ahramat Branch. (a) The two inlets are presently covered by sand, thus invisible in optical satellite imagery. (b) Radar data, and (c) TanDEM-X topographic data reveal the riverbed of the Sakkara Inlet due to radar signals penetration capability in dry sand. (b) and (c) show the causeways of Pepi II and Merenre Pyramids, from Dynasty 6, leading to the Saqqara Inlet. The Valley Temple of Pepi II Pyramid overlooks the inlet riverbank, which indicates that the inlet, and thus Ahramat Branch, were active during Dynasty 6. (d) Radar data, and (e) TanDEM-X topographic data, reveal the riverbed of the Dahshur Inlet with the Bent Pyramid’s causeway of Dynasty 4 leading to the Inlet. The Valley Temple of the Bent Pyramid overlooks the riverbank of the Dahshur Inlet, which indicates that the inlet and the Ahramat Branch were active during Dynasty 4 of the Old Kingdom. Ghoneim et al. (2024).

The satellite radar data suggests another inlet is located about 6 km to the north of the Dashur and to the west of the ciry of Memphis, which Ghoneim et al. refer to as the Sakkara Inlet. This is interpreted as a broad river, which would have been 600 m wide where it met the Ahramat Branch. The causeways of the Sixth Dynasty pyramids of Pepi II and Merenre, both part of the Sakkara Necropolis, have causeways which lead to the Sakkara Inlet. The causeway of Pepi II's pyramid runs northeast from the pyramid, across the Sakkara Plataeu to reach a valley temple located on the south bank of the Sakkara Inlet. The causeway of the Merenre Pyramid runs 350 m southeast from the pyramid, reaching the north bank of the Sakkara Inlet. Together these pyramids indicate that the waters of the Ahramat Branch were high enough during the Sixth Dynasty to flood at least the lower parts of the western inlets, enabling their use as waterways for the shipping of building materials. However, no Fifth Dynansty pyramids are located on the inlets, suggesting that the waters were lower during this interval.

Ghoneim et al.'s data set also indicates the Fourth Dynasty pyramids of Khafre, Menkaure, and Khentkaus, located on the Giza Plateau, had causeways leading to a smaller, but clearly still significant, inlet of the Ahramat Branch, which they term the Giza Inlet. The Khufu Pyramid (the largest of the Egyptian pyramids), appears to have been connected to the main Ahramat Branch. The locations of these pyramids and their causeways offer further proof that the Ahramat Branch and its eastern inlets were active waterways during the Fourth Dynasty, and fits with previous studies which have found evidence for marshy or riverine environments on the floodplains to the east of the Giza Pyramids during the Old Kingdom.

TanDEM-X data shows, in 3D, a clear topographic expression of a segment of the former Ahramat Branch in the Nile floodplain in close proximity to the Giza Plateau. The causeways of the four Pyramids lead to an inlet, which is named the Giza Inlet, that connects from the west with the Ahramat Branch. These causeways connect the pyramids with valley temples which acted as river harbours in antiquity. These river segments are invisible in optical satellite imagery since they are masked by the cultivated lands of the Nile floodplain. The photo shows the valley temple of Khafre Pyramid. Ghoneim et al. (2024).

Ghoneim et al.'s findings suggest that water levels in the Ahramat Branch were high during the Old Kingdom of Egypt, and particularly high during the Fourth Dynasty, after which they began to decline. This correlates with previous studies which have found that the discharge from the Nile into the Mediterranean was particularly high during the Fourth Dynasty, but decreased significantly afterwards, with the lowest output of the entire Pharaonic period seen during the Fifth and Sixth dynasties. Water levels in the Ahramat Branch appear to have been much lower during the Middle Kingdom, with structures assumed to have been built close to water much further to the east than in the Old Kingdom. This is at odds with previous studies of the hydrology of the Middle Kingdom, which have suggested a predominantly wet climate, with sporadic severe droughts. Ghoneim et al. explain this discrepancy as being due to the Ahramat Branch migrating laterally to the east, rather than simply containing less water, as in the Fifth Dynasty, though with a similar result as the building of new structures migrated eastwards.

Ghoneim et al. suggest that the eastward migration and then failure of the Ahramat Branch of the Nile may have been due to tectonic activity, as the Nile Delta and floodplain slowly tilted to the northeast, causing the western part of the floodplain to become elevated. This would lead the Ahramat Branch to migrate to the east, and eventually fail as the upper portion of the Branch fused with the main Nile channel. This eastern movement would also lead to the western portion of the floodplain to become more arid, enabling the sands of the Western Desert to intrude into the area, which would in turn lead to a higher sedimentation rate within the river, and a tendency to silt up during intervals of lower flow. 

During the First Intermediate Period, which separates the Old Kingdom from the Middle Kingdom, Egypt experienced a prolonged drought, with settlements which had been prosperous during the Old Kingdom being engulfed by sands from the Western Desert. The Ahramat Branch seems to have significantly silted up during this interval, causing it to migrate further eastwards when wetter conditions returned prior to the rise of the Middle Kingdom.

During the Old Kingdom the Ahramat Branch was still connected to a number of inlets from the west, which were likely remnants of active drainage systems in the Tertiary or Pleistocene, when the Sahara was green and rainfall abundant across the region. These inlets would most probably have been fed from the Ahramat Branch rather than have carried water into it by the Old Kingdom, providing sheltered areas where the water would have been predicably calm, ideal for unloading materials for major construction materials, but would have dried up as the climate become more arid and the river shifted to the east.

Both of the sediment cores show an abrupt shift from well sorted medium sands to a more variable system with layers of gravel, fine sand, shell and other material, which Ghoneim et al. interpret as a sign of a shift from a constant, high-energy system within a deep, strongly-flowing river, to a more variable environment with a typical weaker flow, but periodic flood events. Two cores with similar profiles were previously drilled close to Giza, where they were interpreted as evidence for a Late Holocene floodplain palaeo-environment, utilised by people and prone to flood events. Further coring is likely to determine more features of the Ahramat Branch and the wider Nile floodplain.

Ghoneim et al. suggest a connection between the Ahramat Branch and the Bahr Yusef, a heavily canalized waterway connecting the Fayum Oasis to the Nile. It is likely that this waterway originally flowed northward before turning west and flowing into the Fayum Depression; the waterway currently bends very sharply westwards into the depression, possibly as a result of Human interference. The British Egyptologist John Römer has suggested that during the Middle Kingdom a dam was constructed which prevented the Bahr Yusef from flowing further to the north when its sluices were closed. Such a structure would have enabled the Egyptians of the Middle Kingdom to control the flow of the Ahramat Branch, or store water in the Fayum Depression. 

Ghoneim et al. believe their evidence demonstrates the presence of a major former channel of the Nile, which they term the Ahramat Branch, which ran past the foothills of the Western Desert Plateau, the area where the majority of the Ancient Egyptian pyramids are found. The scale of this waterway, its proximity to the pyramids, and the numerous pyramid causeways which terminate at its banks, all strongly imply the branch was active during the Old and Middle Kingdoms, and was used as a navigable waterway, used to shift materials by the people of the period. Such a waterway would have provided an important transport link to the Ancient Egyptians, connecting towns and religious centres which have hitherto appeared disconnected. The eastward migration and eventual disappearance of this waterway, was driven by a combination of tectonic movements and the incursion of wind-blown sand from the Western Desert, combined with increasing desertification within the Great Sahara region, and the Nile Valley towards the end of the Old Kingdom.

The study shows the value of combining data from satellite imagary with drilled cores, the combination of which enabled the discovery of a significant waterway, which would have played a major role in the lives of the ancient inhabitants of the region.

This discovery will enable archaeologists to gain a much better understanding of the placement of settlements and temple complexes in Ancient Egypt, potentially leading to the discovery of new sites, and providing an opportunity to protect these sites from spreading urbanization in the region. 

See also...

Letti Desert 1: A new archaeological site associated with the ancient African Kingdom of Kerma.

The ancient Kingdom of Kerma is one of the oldest known states in Africa, emerging in the third millennium BC from the urbanisation of pastoral communities in the Selim Basin of the Third Cataract of the Nile, and persisting until 1504 BC, when it was conquered by the Egyptian Pharaoh Thutmose I. The Kermans built distinctive urban centres with monumental buildings and necropolises, although these have only been extensively studied around- the Third Cateract, with some funerary cites around the Fourth Cataract also known.

In a paper published in the journal Antiquity on 1 December 2023, Piotr Osypiński of the Institute of Archaeology and Ethnology of the Polish Academy of Sciences, Marta Osypińska of the Institute of Archaeology at the University of Wrocław, Justyna Kokolus, an independent researcher from Stara Dąbrowa in Poland, Paweł Wiktorowicz, also of the Institute of Archaeology and Ethnology of the Polish Academy of Sciences, Roman Łopaciuk of the Institute of Mediterranean and Oriental Cultures of the Polish Academy of Sciences, and Amel Hassan Gismallah of the National Corporation of Antiquities and Museums in Khartoum, describe a new archaeological site associated with the Kingdom of Kerma, from the Letti Basin of the Middle Nile Valley in Northern Sudan.

Osypiński et al. identified a number of new sites on the edge of the desert in the Letti Basin, sites which would have been located in close proximity to the seasonally overflowing Nile at the time when Kerma existed. Some of these sites appear to have been extensive settlements, from which were recovered characteristic Kerman ceramic objects, Animal bones, and stone tools, as well as carrying out excavations at one site, named Letti Desert 1.

Middle part of the Nile Valley and location of site Letti Desert 1. Osypiński et al. (2023).

Radiocarbon dates recovered from organic material at Letti Desert 1 suggest that the site was occupied for about 700 years, with the oldest dates being between 2205 and 2020 BC while the youngest come from between 1618 and 1497 BC, around the time of the Egyptian conquest. 

A mud brick building with a surviving thickness of about one metre was established to have been constructed around the beginning of the second millennium BC. Neighbouring structures contained large storage vessels, and had foundations made from boulders up to 3 m in diameter. A granary area with a pavement of square stones was surrounded by post holes. Another area was interpreted to be a metal workshop, with fragments of a large melting pot, and several bronze smelts recovered. 

Architectural elements recorded in the eastern part of the Letti Desert 1 settlement, marked in red. The size of opened excavation is 5 × 5 m. Osypiński et al. (2023).

Analysis of zooarchaeological remains from the site suggests that Cattle became progressively less important over time, with Sheep replacing them as the major form of livestock. This was probably associated with the drying of the local climate and spread of desert. Cattle are known to have remained culturally important, with the rulers of Kerma being buried with Cattle bucrania (the frontal part of the skull, with the horns) in the latest stages of the civilization. However, isotopic studies of these remains suggest that these Cattle came from outside the Nile Valley, possibly from North Kordofan to the south, from where Cattle could be driven to the Letti Basin via the dry channels of Wadi el Melik and Wadi Howar.

Stone pavements in the western part of the Letti Desert 1 settlement, view from the north Osypiński et al. (2023).

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Using strontium isotope ratios to determine the origin of textiles from archaeological sites in Nubia.

The manufacture of textiles by pre-industrial societies was typically a demanding, multi-stage process, which involved obtaining fibres from an Animal or Plant, spinning it into a thread, and weaving it into a cloth, with dyes potentially being added at different stages to achieve colours or patterns. As such, textiles from archaeological sites can be important sources of information about the societies that produced them, giving evidence about trade routes and manufacturing techniques, as well as the social status, gender and age of the wearer. 

Textiles from archaeological sites in Sudan have been studied since the early twentieth century, with material recovered from many sites in the mid Nile Valley. Wool and cotton are the most common fibres in these archaeological assemblages. Linen is also present, but in much lower quantities. Silk has never been produced in Sudan, so any silk discovered there can automatically be assumed to have been imported. Spinning of threads in Sudan was almost exclusively done in the S-direction (anticlockwise), while woven cloths were usually plain tabbies (a plain weave, with warp and weft threads crossing at right angles to form a criss-cross pattern) or weft-facing tabbies (cloths in which the warp is covered up by multiple, complimentary weft layers, enabling the building up of a pattern, which is typically angular in nature), often having bands or stripes in different shades.

However, determining the origin of fabrics from archaeological sites is complex, as plain and weft-facing tabbies are widely manufactured, and the textiles recovered from archaeological sites are typically very fragmentary. Even spinning direction is of limited use, as even in areas where the majority of spinning is done in one direction, the presence of local communities or even individual spinners doing the opposite cannot be excluded.

In a paper published in the Journal of African Archaeology on 11 August 2022, Magdalena Wozniak of the Department of African Studies at the University of Warsaw, and Zdzislaw Belka of the Isotope Research Unit at Adam Mickiewicz University, present the results of a study which used strontium isotope ratios to determine the origin of cotton and wool fragments from Late Antiquity and the Early Medieval Period recovered from archaeological sites in the Middle Nile Valley.

Strontium isotope ratios in water are strongly linked to local geology, and can be preserved in the tissues of Animals and Plants, making them a powerful tool in archaeology. Strontium isotopes have been used to track the movements of ancient Human and Animal groups, as well as tracing ancient trade routes by determining the origin of stone tools, glass, and textiles. This technique requires an understanding of the ratio of the isotopes strontium⁸⁷ and strontium⁸⁶ in the geology of the area, both locally and regionally. Armed with this it is possible to determine whether or not a material (in this case fabric) was manufactured locally, and in some cases where a non-local item originated from. Both Animals and Plants (the producers of wool and cotton) take up strontium from the environment in the ratios at which they are present, without any fractionation, with the strontium isotope ratios found in their tissues reflecting a mixture of that found in the bedrock and overlying soil as well as that from ground and surface water. However, the different ecologies of Animals and Plants mean that even when they live in the same area, they will have slightly different isotopic ratios.

Although obtaining an accurate strontium isotope ratio only requires about 100-150 mg of material, the desiccated and friable nature of most archaeological fabrics means that the process typically leads to the destruction of one or two square centimetres of fabric, so the choice of materials sacrificed must be made very carefully.

Wozniak and Belka used four textile samples from recent excavations near the fourth cataract, made available for the study by the Polish Academy of Sciences, as well as three samples provided by the Sudan National Museum and the National Corporation for Antiquities and Museums in Khartoum. All bar one of these was from a burial site, and all are of either wool or cotton. The sample was chosen to include samples which were presumed to be of both local manufacture and imported. None of the samples showed signs of decomposition or degradation, making it unlikely that they had had their isotope signatures overwritten by strontium from groundwater after being buried, something which can be a severe problem in wetter climates, but is less so in arid Nubia.

The first sample chosen, NT1, was a section of decorated warp-faced woollen fabric (woollen fabric in which the threads are packed together closely, hiding the weft) with roughly 14-16 warp threads and 8 weft threads per cm². This fragment was recovered from the bottom of a funerary chamber beneath Tumulus 24 in the El-Ar 1 cemetery, near the El-Ar village in Shamkhiya District. The El-Ar 1 cemetery has been dated to the 2-3rd centuries AD, with decorated fabrics being very rare there.

Fragment of warp-faced wool tabby, sample NT1. Magdalena Wozniak in Wozniak & Belka (2022).

The second fragment used, NT2, is a piece of dark brown plain tabby woollen fabric, woven from S-spun threads, recovered from the El-Ar 4 Christian cemetery, and which could indicate a date anywhere between the sixth and fifteenth centuries AD. The fragment has 8-9 warp and 7 weft threads per cm², and comes from a section of shroud, which is in turn likely to have been a cloak or blanket used by the buried person and re-used as a shroud upon their death.

Fragment of the wool shroud, sample NT2. Magdalena Wozniak in Wozniak & Belka (2022).

Sample NT6 is a course wool plain tabby, woven with 8 warp and 8 weft threads per cm², taken from the shroud of a naturally mummified body (i.e. preserved by burial in a dry environment, rather than Human intervention). The fragment is brown in colour, and very desiccated. The mummy was buried in a supine position, with hands resting on hips, which is indicative of a Christian burial, again implying the 6th-15th centuries AD.

Close-up of mummy’s shroud, sample NT6. Magdalena Wozniak in Wozniak & Belka (2022).

Sample NT7 is a section of woollen kilim (woven tapestry rug). This has a dense weave with 7 warp threads and 32 weft threads per cm², and is woven in the slit-tapestry style, which creates the same pattern on both sides. The warp is a 2-ply z-spun (clockwise) cream wool, while the weft is single-ply z-spun wool in a variety of colours, including red, green, blue, orange, yellow and pink, giving a pattern of geometric and floral designs against a red background. The kilim was discovered in the town of Meinarti near the 2nd cataract in 1963, and has been dated to the 14th century AD.

Fragment of wool kilim from Meinarti, sample NT7, before conservation. Magdalena Wozniak in Wozniak & Belka (2022).

Sample NT3 is a piece of weft-faced tabby cotton cloth from the El-Ar 4 Christian cemetery. The threads are S-spun and of a golden colour, with the weft threads thicker than the warp threads, and a thread-density of 11 warp threads and 19 weft threads per cm². This is a common, medium-quality cloth type at archaeological sites on the Middle Nile.

Fragment of cotton tabby, sample NT3. Magdalena Wozniak in Wozniak & Belka (2022).

Sample NT4 is a fragment of cotton plain tabby from a Late Antique (2nd to 5th century AD) burial site at El-Ar. It is comprised of Z-spun white threads with traces of blue, green, and red pigments, probably a sign of resist dying (dying a finished fabric, while using wax or a similar substance to control which parts of the fabric the dye reaches), and a thread density of 22-24 threads per cm² for both warp and weft.

Bi-coloured threads from the cotton tabby, sample NT4. Magdalena Wozniak in Wozniak & Belka (2022).

Sample NT5 comes from the shroud of a naturally mummified body of unknown providence in the collection of the National Corporation for Antiquities and Museums. The textile is desiccated, low density, cotton tabby with a thread count of 8 warps and 8-9 wefts per cm². The threads are Z-spun, and have a golden colour. This mummy was also preserved in a supine position, with hands on hips, indicating a Christian burial, between the 6th and 15th centuries AD.

Fragment of cotton tabby woven from Z-spun threads, sample NT5. Magdalena Wozniak in Wozniak & Belka (2022).

Precambrian rocks of the Arabian-Nubian shield are widely exposed between the 2nd and 5th cataracts of the Nile. These exposures show a large variety of magmatic and metamorphic rocks, separated by suture zones with small occurrences of ophiolites and deep-water sedimentary rocks. To the west of the Nile Valley these are bordered by younger sedimentary rocks, predominantly Silurian sandstones. These rocks are overlain unconformably by the rocks of the Nubian Sandstone, which spreads across much of northern Africa, and includes a range of continental, esturine and marine sediments (predominantly sandstones), which in Sudan are predominantly of Cretaceous age. These Nubian Sandstone deposits have been mostly eroded away in the northeast of the country, exposing the underlying Precambrian basement, but extensive exposures are still present in the Bayuda Desert in the south, and the area to the west of the Nile. Tertiary Basalt rocks, which have intruded into these overlying strata, are exposed in the south of the country, around Abu Hamad. The floodplains of Nile Valley is also home to an extensive succession of Tertiary Sediments. 

Simplified geological map of northern Sudan. Red asterisks  indicate places where the investigated wool and cotton textiles were found. Numbers refer to the samples numbers. Inset shows the location of the study area. Wozniak & Belka (2022).

The volcanic rocks of the Precambrian basement of northern Sudan have strontium⁸⁷/strontium⁸⁶ ratios in the range 0.7024 to 0.7071, while the plutonic and metamorphic rocks of the basement have ratios in the range 0.7158 to 1.0039. The Cretaceous sediments of the Nubian Sandstone have strontium isotope ratios reflective of those of the basement rocks, with two clusters of values, around 0.7070 and 0.7160.

The alluvial sediments of the Desert Nile Valley are dominated by material derived from the Blue Nile and Atbara rivers, which drain from the Ethiopian Highlands, an area dominated by Cainozoic Volcanic rocks. These sediments have isotopic ratios in the range 0.7047 to 0.7076, a range which includes that of modern Nile water, at 0.7062. Nile muds dating from the end of the African Humid Period, about 45 000 years ago, show a strontium isotope ratio of 0.7052–0.7057, while those dating from between 1000 BC and 500 AD (i.e. between 3000 and 1500 years ago) show an isotope range of 0.7058–0.7076.

Samples NT1, NT2, and NT6 are all low-density woollen tabbies made from S-spun threads, technologically consistent with local manufacture. Sample NT1 contains cream and dark wool, used to make a pattern, while NT1 and NT6 are made entirely of undyed, dark wool. Lighter, cream-coloured wools are rare in the El-Ar assemblage, which may reflect the genetic structure of the local flocks (i.e. many brown Sheep and few cream Sheep). Alternatively, the local Sheep of the period may have been entirely brown, with cream wool being an imported commodity.

Sample NT7 is quite different from these, made up of coloured, Z-spun threads woven together using the split-tapestry technique to produce a decorative pattern, which is likely to indicate that this was an imported item. Furthermore, furthermore, the red dye used on some of the wool appears to have been treated with a lac dye, derived from the Scale Insect, Laccifer lacca, which is found in South and Southeast Asia and South China, but quite alien to the Nubia, where red dyes were traditionally derived from the Madder Plant. This apparently non-local item dates from the 14th century, a time when Meinarti was occupied by the Beni Ikrima, a nomadic group from the Maghreb region.

All four wool samples yielded strontium isotopic ratios within the range 0.7075 to 0.7084. In order to better compare these to the local environment, Wozniak and Belka also obtained strontium isotope ratios from Sheep and/or Goat remains (the two are hard to tell apart) from several archaeological sites between the 2nd and 4th cataracts. All of these remains are known to be older than the wool samples, dating to between 2500 and 500 BC, and gave isotopic ratios in the range 0.7068 to 0.7082 (one set of remains gave a much higher reading, of 0.7109, though this is likely to indicate that the Animal was of non-local origin).

Diagram showing the strontium isotope signatures of the  investigated wool textiles (yellow spots; numbers refer to sample numbers) in comparison to Strontium isotope  composition of Ovis/Capra remains found in the region  between the 2nd and 4th cataracts. Wozniak & Belka (2022).

Three of the investigated wool samples, NT1, NT6, and NT7, had isotopic ratios entirely consistent with archaeologically derived Sheep/Goat remains from the region, and the fourth, NT2, fell only slightly outside this range, and still within the range of Cattle and Human remains from the Desert Nile Valley.

Of the three cotton samples, only one, NT3, was made of a yarn spun in an anticlockwise, S-direction, typical of local manufacture in Nubia or Egypt. The other two, NT4 and NT5, were spun in a clockwise, Z-direction, which may indicate non-local manufacture. One of these, NT4, also shows signs of a resist-dying technique, not known in Nubia in the 2nd-5th centuries AD, but common in textiles from India during this period.

These three samples show a narrow isotope ratio range, from 0.7084 to 0.7086, which makes it likely that they were derived from crops grown within a limited geographical area. As a crop, cotton requires a rather specific set of conditions, with a hot dry climate, and large amounts of available water for several months of the year. This can be provided in the Nile Valley between the confluence of the White and Blue Niles and the 2nd cataract, although water and plants derived from this region show isotope ratios below 0.7075, ruling this region out as an origin point for the cotton in the study. Cotton is also grown around the Nile Delta, and ancient cotton fibres and seeds have been recovered from other sites along the Lower Nile, suggesting that cotton may have once been grown more widely. Strontium isotopic signatures are not available for sediments from all of these areas, but the isotopic signature of the Nile water, at about 0.7069, makes it unlikely that any of these floodplains have an isotopic ratio above about 0.7075. Similarly, the sediments of the Atabara and Blue Nile valleys have average isotope ratios between 0.7041 and 0.7060. All of these locations therefore seem unlikely as a point of origin for the cotton used to make the textiles included in the study. 

However, cotton grown in the Western Desert of lower Nubia typically has an isotopic value of about 0.7085, and limestones from the Western Desert of Egypt can have strontium isotope signatures in the range 0.7077 to 0.7078. Cotton is known to have been grown in this region in the 2nd-3rd centuries AD, using irrigation systems which drew upon shallow groundwater reservoirs, supplied by rainwater that had filtered through Eocene carbonates, which could conceivably produce a cotton with a strontium isotopic signature of about 0.7085.

Cotton is also known to have been produced in Meroe, on the lower White Nile to the south of Khartoum, during the Roman period, although both the water and plants from this region tend to have a higher isotopic ratio than the cotton from the study, excluding this region as a point of origin. 

Diagram showing the strontium isotope composition of the investigated cotton textiles (green spots; numbers refer to samples) in comparison to Sr isotope composition of selected elements of the natural environment in the Nile and White valleys. Wozniak & Belka (2022).

There is strong evidence for the production of cotton in Egypt and Sudan in Roman and later times, but the possibility of material also being imported from further afield should not be ruled out. Cotton was widely cultivated in India and on the Arabian Peninsula during antiquity, and both raw cotton and finished textiles could easily have been imported to Nubia via the Red Sea. Cotton seeds and textiles excavated at Mleiha in the modern United Arab Emirates have been shown to have originated from western India by their strontium isotope ratios. Unfortunately, strontium isotope information is only available for a few locations on the Arabian Peninsula or from India or Pakistan. However, several regions would be compatible with the isotope signatures obtained from the cotton samples, including the lower Indus River Basin, in India and Pakistan, the Kathijawar Peninsula on the west coast of India, the area covered by modern Kuwait, and the Oman Peninsula.

The isotope signatures obtained from the wool samples from archaeological sites in the Nubian Nile Valley all support a local origin. This is also supported by the technological features of three of the samples, NT1, NT2, and NT6, but not the fourth, NT7. This sample, a kilim rug from 14th century Meinarti, appears to have been made with a technology entirely alien to this part of the Nile Valley. However, it also dates from a time when the city of Meinarti was occupied by an alien group, the Beni Ikrima, who originated from the Maghreb region. Since the Maghreb has a geology with similar strontium isotopic ratios to that of northern Sudan, it is possible that the kilim was brought to the area by the Beni Ikrima from their homeland. However, it is also possible that the kilim was made locally by Beni Ikrima craftspeople from wool obtained from local, Nubian, flocks. Wozniak and Belka conclude that, given the available isotopic evidence, the more likely scenario is that the kilim was made locally, contrary to previous expectations.

In contrast, the isotopic signature of the cotton samples examined fits poorly with an origin in the Nile Valley. The samples all have very similar isotopic signatures, which seems to imply a common origin, although this is at odds with the different spinning techniques used. One of the samples, NT3, has an isotopic signature that fits well with the Dakhla/Kharga oasis in the Egyptian Western Desert, which has previously been identified as a possible site of ancient cotton cultivation. This piece also shows a technology consistent with production in the Nile Valley, notably an S-spun yarn. Importing cotton textiles from an oasis in the Western Desert would only make sense if local, Nubian, production was failing to meet demand. The frequency of cotton fabrics from archaeological sites in Nubia has been observed to have dropped during the Late Antique and Early Medieval periods, so this is not implausible, although an alternative explanation could be that the deceased person for whom this item was used as a shroud had travelled during their lifetime, either moving from the Western Desert to Nubia and bringing the cloth with them, or at some point visiting the Western Desert and obtaining the item there.

Sample NT4, on the other hand, appears much more likely to be of Indian origin, where a block printing technique using resist dying was common at this time. The isotopic signature of this sample matches that of the Kathijawar Peninsula on the west coast of India, leading Wozniak and Belka to conclude that this item was most likely imported from India. This adds evidence to the inclusion of the area around the 4th cataract into long distance trade networks, something previously indicated by the discovery of glass beads of foreign manufacture in the region.

Sample NT5 also appears to be non-local in origin, with a Z-spinning technique having been used, and a non-local isotopic signature. However, there is insufficient evidence to give a precise origin for this fragment at this time, with possible points of origin including  Indus River basin in Pakistan, the west coast of India, Kuwait, and the Oman Peninsula.

Although Wozniak and Belka were not able to determine the point of origin of all the fabrics in the study, their study shows the potential for determining the origin of ancient fabrics using strontium isotope ratios. The development of a wider data set of strontium isotope values for textiles could add to the information obtained by examining the technological aspects of textile-making, to provide a better understanding of the manufacture of and trade in cloth in the ancient world.

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Understanding the Roman-style forts of Upper Nubia.

The term Upper Nubia is used to identify the area along the banks of the River Nile between the Third Cataract and the confluence of the White and Blue Niles, and the areas of desert and semi-desert that surrounds it. This area is covered by a huge array of defensive structures, mostly dating to the medieval and post-medieval periods; the exact number of these structures is unclear, although it is probably over 300. Some of these structures have been extensively explored by archaeologists, but most have been only briefly surveyed, if at all. As a result of this, the origin of most of these forts is unclear, with estimates based upon surface materials recovered from the sites or just the general shape of the fortifications. 

The largest of these structures, such as Old Dongola and Bakhit, are still the largest structures ever built in this region, but many are much smaller, representing little more than military towers or fortified houses. Among these varied structures, one group stands out for their similarity, a group of small forts with quadrilateral structures resembling Late Roman fortlets. 

In a paper published in the journal Azania: Archaeological Research in Africa on 2 February 2022, Mariusz Drzewiecki of the Polish Centre of Mediterranean Archaeology at the University of Warsaw, and Aneta Cedro of the Institute of Mediterranean and Oriental Cultures of the Polish Academy of Sciences, examine the origins of these forts and try to understand who built them and why.

Map of the Upper Nubia region of Sudan showing the locations of places mentioned in the text. Black squares mark quadrilateral forts, red squares potential forts. Mariusz Drzewiecki in Drzewieki & Cedro (2022).

Drzewieki and Cedro were able to identify nine Roman-style forts in Upper Nubia, spanning about 550 km of the Nile Valley. These are presumed to have been built during Late Antiquity (the second to seventh centuries AD), a time of significant political change in the region. By the second century AD the Kushite Kingdom of Meroe was beginning to break apart into smaller states. In the fourth century, when the Axumite King Ezana sent an army to conquer the region. By the fifth-to-sixth centuries the region was divided into three kingdoms, Makuria, with its capital at Dongala, Nobadia, with its capital at Faras, and Alwa, with its capital at Soba, which, by the late sixth century, were at war with one-another, having converted to different branches of Christianity; the Makurians having adopted Melkitism, and the other two kingdoms having converted to Monophysitism.

The quadrilateral fort at the top of Jebel Umm Marrahi. Mariusz Drzewiecki in Drzewieki & Cedro (2022).

Drzewieki and Cedro consider that three possible explanations for the forts are plausible. 

Firstly, the forts could have been built by the Kingdom of Meroe towards the end of its existence; this is supported by the locations of the forts, which span the final area which the Kingdom was able to hold onto before its eventual collapse. 

Secondly, the forts could have been built by one of the successor kingdoms which emerged in the fifth-to-sixth centuries. A number of forts between the Third and Fourth Cataracts (further downstream) are considered to have been built by the Kingdom of Makuria, though these are less regular in form than the Upper Nubian forts, being moulded to the local topography. All of the Roman-style forts lie within the boundaries of the historic Kingdom of Alwa, with the most southerly fort, Jebel Umm Marrahi, being only 50 km to the north of the city of Soba, which has led to the suggestion that the forts might have been built by the Alwans.

Finally, Drzewieki and Cedro hypothesise that the first of the forts could have been built by Meroe, but then integrated into the defence system of one of the later states and used as a template for the construction of more forts along the same lines.

The nine forts are remarkably similar in construction. The largest, Hosh el-Kab, is only four times the size of the smallest, Wad Mukhtar. The corners of the forts are reinforced by bastions, and most were built using a vertical masonry technique absent from other sites in the area, including the Makurian forts. 

The Middle Nile forts. Mariusz Drzewiecki in Drzewieki & Cedro (2022).

In order to establish who built the forts, Drzewieki and Cedro reason, it would first be necessary to establish precise dates for their construction. Such dates can be obtained from a range archaeological material, but, for the dating of the construction times, only material from the lowest layers within the forts, and the layers immediately beneath their foundations, should be used. Material obtained from the cores of curtain walls or from higher layers within the forts may also prove useful, but their context must be evaluated very carefully.

Vertical masonry in the fort at Mikeisir. Urszula Stępień in Drzewieki & Cedro (2022).

Examination of material from the lowest layers within the forts can also shed light on the lives of the original occupants of the forts, which in turn may help to understand why the forts were built. Items such as ceramics or organic material can reveal a lot about the daily lives of the people who deposited them, as can presence or absence of luxury items, combined with analysis of any food remains. Were the fortified structures intended to house garrisons, act as storehouses, or as fortified dwellings for whole communities? Were they used over a long period of time, or did their construction relate to some specific threat, after which they were abandoned?

Although the forts are very regular in construction, their distribution is very uneven. As mentioned previously, the southernmost fort, Umm Marrahi, lies only 50 km to the north of the Alwan capital Soba. Three kilometres to the north of this lies the fort of Hosh el-Kab, while 500 m to the east of Hosh el-Kab is the fort of Abu Nafisa. This clustering seems to make it unlikely that all three of these forts were in use at the same time, which prompted  a team from the Polish Academy of Sciences to investigate these sites directly.

The location of Abu Nafisa, Hosh el-Kab and Umm Marrahi. Włodzimierz Rączkowski & Mariusz Drzewiecki in Drzewieki & Cedro (2022).

The fort at Umm Marrahi was surveyed by the British archaeologist Osbert Crawford in the 1950s, and some test excavations were carried out there by a team from Khartoum University in the 1970s. The Khartoum team recovered pottery fragments from the fort and from a nearby cemetery, which were of similar manufacture. Based upon this, it was calculated that the fort was in use at some time between the Late Meroitic and Early Christian periods, between about 325 and 650 AD. A radiocarbon date was established for a piece of pottery, which placed it at between 675 and 975 AD, with a confidence level of 94%, but this cannot realistically be extrapolated to a construction time for the fort. Further investigations in the area in the 1980s shed no further light upon the age of the fort. Neither of the other forts has been formally investigated, though some speculation about their origin has appeared in research publications about the area, with suggestions including Meroitic, Makurian, and Early Medieval.

The Polish Academy of Sciences team carried out fieldwork at Hosh el-Kab and Abu Nafisa in 2018, and at Umm Marrahi in 2019. Initial surveys of the sites, combined with interviews with local residents established that many of the structures visible within the forts were of much later origin than their construction, often dating to the Islamic Period. Umm Marrahi contains a mosque, and several associated buildings, which was constructed by a local Sufi brotherhood, while Abu Nafisa contains the tomb of an Muslim Holy Man, Sheikh Abu Nafisa.

The only structures that could be confidently associated with the construction of the forts are their walls. With this in mind the Polish team dug two excavation trenches along the insides of walls at each fort, where possible doing so at the sites of gates or the corners of the forts. Before doing this a careful surface survey was carried out, and previous excavations left by looters, or where paths or irrigation channels had been cut, were inspected.

The fort at Umm Marrahi showing the location of archaeological trenches. Mariusz Drzewiecki in Drzewieki & Cedro (2022).

Before any excavation work was undertaken, a geophysical survey was carried out at each fort, in order to better understand the organisation and state of preservation of the buildings within them. At Abu Nasifa, an area of 7400 m² was surveyed, with the southeastern corner being excluded from the survey in order to avoid disturbing the tomb of the Holy Man. At Hosh el-Kab an area of 13 300 m² was surveyed, excluding only an area where the site had clearly been damaged beyond the usefulness of such surveys by modern irrigation work. At Umm Marrahi an area of only 1600 m² was surveyed, as the bedrock was exposed in many places at this fort.

The fort of Abu Nasifa is the closest of the three sites to the Nile, and has clearly been flooded on several occasions since it was in use. Both the excavations and the geophysical survey carried out here uncovered massive alluvial deposits, with little archaeological evidence from the time of the fort's use remaining. However, the remains of a settlement pre-dating the fort were uncovered, and a number of potentially datable fragments of charcoal collected, potentially providing a maximum age for the fort.

The fort at Abu Nafisa fort showing the location of the archaeological trenches. Mariusz Drzewiecki in Drzewieki & Cedro (2022).

The walls of Abu Nafisa were worn down to their foundation, although it was possible to confirm that these walls were made using a vertical masonry technique. Most of the material collected here came from the surface or upper layers within the trenches, and could be dated to the Funj period (1504-1821 AD). However, a few fragments of older pottery and some beads were recovered from the lowest layers of the fort settlement, these being referable to the post-Merotic/Christian transition period (fifth-to-sixth centuries).

Samples of pottery associated with the beginning of the forts at Abu Nafisa (a)–(c) and Hosh el-Kab (d)–(f). Aneta Cedro in Drzewieki & Cedro (2022).

The largest of the forts surveyed was Hosh el-Kab, which is also distinctive in having thirteen bastions strengthening its corners and curtain walls. It is close to Abu Nafisa, but further from the river, towards the edge of the desert. The site was badly damaged in 2013-4, when a 10 m wide irrigation trench was cut through it. The walls remain to a height of about 70 cm, and are made of irregular stones, bound with mortar, with no signs of vertical masonry ever having been present. 

The fort at Hosh el-Kab with the remains of a church shown by an arrow. Mariusz Drzewiecki in Drzewieki & Cedro (2022).

Geophysical surveys within Hosh el-Kab suggested that most of the buildings that had stood there were made from mud bricks. As with Abu Nafisa, most of the material found within the fort was close to the surface, and dates from the Funj period or later. Some pottery fragments dating to the post-Merotic/Christian transition period were found in the deeper layers of the trenches, and in the area around a former church within the fort.

The fort at Hosh el-Kab in 2018. Mariusz Drzewiecki in Drzewieki & Cedro (2022).

Unlike Abu Nafisa and Hosh el-Kab, the fort at Umm Marrahi is located on top of a hill, and contains numerous stone-built buildings, although investigation of these suggests that all are quite recent in origin. The fort is built directly onto the bedrock, which is still very close to the surface at the centre of the fort. Around the walls, however, a sediment layer was present, up to 1.4 m in depth. Excavations produced material dating to the early Holocene, post-Meroitic, early Christian, Funj and modern eras, with the earliest layers within the walls yielding fragments of cooking and storage vessels, as well as pieces of thin, black-burnished handmade bowls of post-Meroitic origin. No pottery of Merotic origin was found anywhere within the fort, which Drzewieki and Cedro take as evidence that the fort post dates the Kingdom of Meroe.

A total of 22 organic samples were recovered during the excavations, of which 19 yielded radiocarbon dates. The earliest of these dates are from the first half of the fifth century AD, roughly 70 years after the Axumite King Ezana's invasion of the area. Based upon the dates recovered, the most likely origin of all the forts was in the late sixth or early seventh century AD.

The best dated site is Abu Nafisa, the construction of which can be placed between 561 and 574 AD, based upon both material from below the fort and material from the lowest level within the fort. Hosh al-Kab is probably slightly younger, with the lowest layers here dated to between 571 and 604 AD. Umm Marrahi is the least well constrained, but was probably built between 536 and 564 AD. All of these dates are around 200 years after the fall of Meroe, ruling out a Meroitic origin of the forts.

At Hosh el-Kab and Umm Marrahi, the forts appear to have remained in use into the Early Christian era, but then to have been abandoned until the Funj period, with no material dating from the Classic and Late Christian periods present. Abu Nafisa appears to have been abandoned earlier, with no Early Christian material present. 

This suggests that all the forts were only in use for a short period of time, and that Abu Nafisa was abandoned quite soon after its construction. This may relate to the site's vulnerability to flooding; considerable amounts of alluvial sediment were found within the walls of the fort, and the site was inundated during the floods which hit Sudan in 2019. If this was also the case in the sixth century, then it is quite possible that the fort was abandoned in favour of the dryer site at Hosh el-Kab, which would also explain why the two sites were so close together. This larger fort was at the edge of the water in 2019, suggesting that its builders had taken the likely extent of flooding into account when building it.

Google Earth images of Abu Nafisa and Hosh el-Kab during the flood of 2019. Drzewieki & Cedro (2022).

While vertical masonry was used at Abu Nafisa, it is absent at Hosh el-Kab and Umm Marrahi. If Abu Nafissa does predate Hosh el-Kab, this may indicate that Umm Marrahi was built at roughly the same time as the latter; since it was only half the side of Hosh el-Kab it may have been an auxiliary post intended to work in conjunction with the main fort in some way. Whatever the precise relationship between the forts, they clearly point towards the area being a site of strategic importance in the second half of the sixth century AD.

The material recovered from the lower layers within the forts was remarkably uniform across all three sites, with the smallest civil sites in the Middle Nile Valley producing a much more varied range of material, including luxury items and goods brought in from long distances away, all of which were missing from the forts.

The geophysical survey carried out at Hosh el-Kab found traces of mud-brick buildings along the southern and parts of the northern walls of the city, as well as free-standing buildings, including a church, throughout the enclosed area. This was confirmed by a small trench on the northern wall, which uncovered the remnants of a mud-brick structure. Early Christian pottery and other material were found in the area around the church. 

Most of the original structures within Umm Marrahi appear to have been demolished in the nineteenth, twentieth, and twenty first centuries, to make way for newer construction. The buildings of Abu Nafisa appear to have been almost totally eroded away by the action of repeated flooding, although a few places may show the remains of stone floors of buildings.

Pottery is the most common material at all three sites, with a total of 1554 fragments collected in total. The distribution of this pottery was not even; Abu Nafisa, having apparently been used only briefly and then subjected to repeated flooding events, unsurprisingly yielded little pottery. Hosh el-Kab had apparently been the subject of numerous excavations in the post-medieval and modern periods, during which much material had been removed, probably for construction purposes in local villages. Umm Marrahi became a centre of religious activity in more recent times, and as such had been relatively undisturbed by local villagers. Excavations here yielded a range of pottery from different periods. However, none of the sites was completely excavated, and it is likely that the discovered pottery represents only a fraction of the total amount present.

The most distinctive feature of the pottery from the lowest layers at Umm Marrahi is that none of it is wheel-made. All of the pottery is hand made, and though it can be divided into coarse ware with thick walls and crude outer surfaces, and finer ware with smoother surfaces, the difference between the two appears to be purely functional. The finer ware, which is usually covered by a slip, generally black in colour, and burnished or polished, and occasionally decorated, is used exclusively for the production of small bowls or dishes. The cruder pottery, which lacked any slip or burnishing, and often preserved the fingerprints of its makers, was used for making larger bowls.

Black-polished bowls from the earliest phase of the Umm Marrahi fort. Aneta Cedro in Drzewieki & Cedro (2022).

One distinctive group of larger bowls have a shallow, open shape with vertical or steeply sloping walls. The upper parts of these walls are typically thicker, and have a pattern of fingerprints or diagonal cuts along their rims. Fragments of these bowls were found at Umm Marrahi, Abu Nafisa, and Hosh el-Kab, and are also known from Soba. Some of these bowls have soot on their outsides, suggesting that they may have been used for cooking. Fragments of a type of bowl known as a doka, used for the baking of flatbread, were also found, as were pieces of what appear to be storage vessels, including short, wide-mouthed bottles, plain neckless jars, and 'beer jars' which have globular bodies and slender necks.

Examples of coarse ware pottery from the earliest phase of the Umm Marrahi fort. Aneta Cedro in Drzewieki & Cedro (2022).

A lot of the pottery from the lowest layers at Umm Marrahi is very similar to pottery previously recovered from the city of Soba. Notable example of this are the presence the black slip-ware and of a type of thin-walled bowl with carinated (ridged) walls and either a black or red slip. Examples of this sort of bowl, with both black and red slips, have also been recovered from Soba.

Examples of bowls from the Umm Marrahi fort (left) and their parallels from Soba (right). Aneta Cedro and Ewa Czyżewska-Zalewska in Drzewieki & Cedro (2022).

While the lowest layers at Umm Marrahi produced only hand-made pottery, the higher layers did produce wheel-made pottery. All of this could be dated to the Early Christian period, although some of it was clearly inspired by Late Roman patterns. Again, this was similar to material found at Soba, and likely to have been made in the same workshops.

Some of the pottery items found at Umm Marrahi showed signs of repair, including items which would normally have been considered to have been of low value, such as course bowls and storage jars, but which were apparently worth having their lives extended here. Also found were two potsherds which had been polished and cut into circular shapes, which Drzewieki and Cedro take as evidence that they had been used as spindles, thus providing evidence of yarn production.

The excavations carried out at Umm Marrahi by a team from Khartoum University in the 1970s also uncovered ceramics, including two complete vessels, a small bowl and a cooking pot. All of this pottery conformed to the same types recorded by the Polish team. Evidence of the repair of pottery was also present in this sample.

The pottery from Umm Marrahi is remarkably functional, with no examples of 'luxury' items, or anything else that might be used to denote social status. Even the best made bowls, while well executed, are strictly functional in form, and were probably made at local workshops. No amphorae, or other objects which might be associated with long-distance trade were found.

After pottery, the most common finds at the sites were Animal remains, comprising a collection of 562 bones, teeth, and fragments. The majority of the material from the lowest layers can be assigned to Sheep and/or Goats, with a smaller amount of Cattle remains. Also present were pieces of bone from a Rodent and a Hippopotamus. Notably absent were the remains of any non-consumed domestic Animals (such as Dogs, Cats, Donkeys, or Camels), or bones from parts of Animals not typically consumed (such as the phalanges), suggesting that all the Animal remains originally came to the site as meat for consumption, not live Animals.

The preponderance of Sheep/Goat remains, particularly in comparison to the number of Cattle remains, is puzzling, as at other sites in the area, including Soba and Makurian sites, the reverse is true, with Cattle remains being the most abundant. At Soba, the remains of Pigs are also quite common, but these are absent at the forts.

A very small number of other items were uncovered at the forts, including nine beads, eleven stone tools (grinding stones and pestles), and a piece of copper. The complete lack of luxury goods at the sites suggests that the inhabitants were not members of a ruling or wealthy class. The uniform nature of the pottery implies that everyone present was using essentially the same utensils, storage spaces, and goods, while the preserved remains of the original buildings at Hosh el-Kab reveals that living spaces were arranged according to a regular plan.

This does not necessarily imply that all of the residents were of equal status. The fortified nature of the buildings makes it likely that these were military outposts, where rank would probably be clearly recognised, even if the materials used by all ranks were strictly functional. The one problem with this interpretation is that no weapons have been found at the site, which would normally be expected from a garrison fort, although most weapons known from post-Meroitic Nubia are known from burial sites, so this is perhaps not as remarkable as it would be elsewhere in the world.

Part of the problem with interpreting the purpose of the forts is that the political situation in Upper Nubia in the sixth century is poorly understood. The Byzantine scholar and historian John of Ephesus (c.507-c.588 AD) records that in the latter part of the sixth century the kingdoms of the Middle Nile were starting to convert to Christianity, as well as frequently fighting amongst themselves. Little is directly recorded about Alwa or its neighbouring states, but a line of forts between Alwa and Makuria probably implies that the two states were at least close to conflict with one-another. There was also a potential for conflict with Beja nomads inhabiting the Eastern Desert, as well as various nomadic groups crossing the Bayuda Desert.

The King of Alwa is known to have been baptised into the Monophysite branch of Christianity in 580, by the Byzantine missionary Bishop Longinus, who had travelled from Nobadia for the event. Some correspondence between the two monarchs survives, and suggests that the conversion was part of the forging of an alliance against the Makurians, although what this dispute was about, when it started, and how long it lasted, are all unclear.

The Kingdom of Alwa may have reached as far as the Fourth Cataract in the sixth century, with the last of the nine forts being at El-Ar, just upriver of that cataract. This is a huge area, including all of the central part of the former state of Meroe. However, by the end of the sixth century the Kingdom of Makuria is known to have reached to the Fifth Cataract, presumably at the the expense of the Alwans. Some of the forts in this region, such as Mikeisir, were abandoned at this time, while others, such as El-Ar, were modified and used for other purposes, while forts in the Makurian style, such as Karmel and Ras el Gezira, were erected. 

How long this conflict lasted is unclear, though the forts at  Hosh el-Kab and Umm Marrahi clearly remained in use into the Early Christian period. By the middle of the seventh century the Kingdom od Nobadia had fallen to an Islamic Arab army under Abdallāh ibn Sa΄d ibn Abī Sar, which had marched up the Nile and was now threatening Makuria, possibly lessening that state's enthusiasm for war with Alwa.

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