Roman silver ingots recovered from black market in Ukraine.

Three Roman silver ingots, each stamped with a coin issued by Constantine the Great, have been recovered by authorities in Zakarpattia Oblast (Transcarpathia), following an attempt to sell one of them via the internet, according to a press release issued by the National Museum of the History of Ukraine on 13 August 2024. The seller, who has been arrested and is likely to face trial, claimed that the ingots were found in a garden in the Khust area by his grandmother, and that he found them in her basement after she died. 

The Roman silver ingots recovered in Ukraine. National Museum of the History of Ukraine.

The ingots each been bear a coin stamp which would have otherwise have been used to stamp golden coins at Augusta Treverorum (the modern city of Trier in Germany) between 310 and 313 AD, following Constantine's victory over the Franks. Ingots stamped in this way are known to have been given as gifts be Roman emperors following important events, although no such items associated with Constantine's victory over the Franks have previously been found. Constantine returned to Rome shortly after his victory, to face his rival, Emperor Maximillian, notably converting to Christianity before that battle, and promising to make the whole Roman Empire Christian should he win, which he subsequently did. 

The style of the ingots, a double axe-labrys, is consistent with manufacture in the late third or early fourth century AD, and the ingots each weigh 342 g, equivalent to the weight of 100 siliqua, a silver coin introduced by the Emperor Diocletian in 294 AD during his reform of imperial currency; prior to this Roman ingots would typically have weighed 328.9 g, one Roman Libra (Pound). It is likely that the three ingots would have been bound together with a silver ribon when given as a gift.

Quite who the gift was given to is unclear. Ukraine was outside the Roman Empire, and in the early fourth century would have been inhabited by a mixture of Dacians and Germanic tribes. The Romans are known to have made extensive use of mercenaries from outside the Empire during this period, and it is possible that the gift was given to a king or nobleman from the region who had served in the Roman Army, although a gift of this size would have been significant, and it is surprising that the name of a person important enough to receive it would not have been recorded.

While metal ingots from the Roman Empire are not unusual, ingots stamped with coin impressions in this way are very rare, with only eleven examples known to have survived, including the three from Khust, making their discovery highly significant.

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Determining the origin of the silver in the bracelets of Queen Hetepheres.

Egypt lacks any notable silver deposits of its own, and silver objects were rare during the Old Kingdom, with the metal not becoming a commonly imported commodity until the early Middle Kingdom, about 1900 BC. Silver objects dating to the Old Kingdom are therefore extremely rare, and generally associated with high status royal burials. One of the most notable groups of silver objects is a collection of bracelets from the tomb of Queen Hetepheres, the wife of the Pharoah Sneferu, who was the first ruler of the Forth Dynasty and reigned from approximately 2613 to 2589 BC, and mother to Pharoah Khufu, who built the Great Pyramd at Giza. 

The origin of silver from this period is uncertain. It could potentially have come from local sources which have since been lost; the Ancient Egyptians are known to have mined gold extensively, and seams of silver in gold-bearing rocks are not unusual. Alternatively, silver could have been imported from one of the cities of what is now Syria, most likely Byblos on the southern coast, which Egypt had been trading with since at least the Naqada IIIA1 Period (about 3320 BC), although cities further north were also traded with, with Elba having been added to the trade network by the end of the Old Kingdom, about 2300 BC.

The tomb of Queen Hetepheres at Giza was uncovered in 1925, by a joint expedition of Harvard University and the Museum of Fine Arts. This tomb had been undisturbed till this point, and contained a trove of artefacts including gilded furniture, gold vessels and jewellery. Among this jewellery was the remains of a wooden box containing twenty silver 'deben' rings (a 'deben' was a unit of weight, although the value of this appears to have changed over time). The rings were in a variable state when uncovered (unlike gold, silver will corrode over time), and the whole collection was sent to the Egyptian Museum in Cairo. In 1947 two intact rings from this collection, along with a number of fragments of silver from rings which had disintegrated, was gifted by the Egyptian Museum to the Museum of Fine Arts.

When worn, these rings would have been bracelets, with five worn on each limb. They are made from thin sheets of silver folded into a cresent shape, so that there is a cavity on the inner side, and inlaid with turquoise, lapis lazuli and carnelian, in a style which clearly establishes their Egyptian origin. A metallurgical analysis of the metal was carried out in the 1920s, finding it to be 90.1% silver, 8.9% gold, and 1.0% copper, but the distribution of the gold was uneven, giving the bracelets yellowish patches. Since that time no further metalogical examination of the rings has taken place.

In a paper published in the Joutnal of Archaeological Science: Reports on 1 May 2023, Karin Sowada of the Department of History and Archaeology at Macquarie University, Richard Newman of the Museum of Fine Arts, Francis Albarède of the Ecole Normale Supérieure de Lyon, Gillan Davis of the Australian Catholic University, Michele Derrick, also of the Museum of Fine Arts, Timothy Murphy of the School of Natural Sciences at Macquarie University, and of Newspec Pty Ltd, and Damian Gore, also of Newspec Pty Ltd, present an updated metallurgical analysis of the silver from the bracelets of Queen Hetepheres, and discuss the implications of their results for the likely origin of this metal.

(A) Bracelets in the burial chamber of Tomb G 7000X as discovered by George Reisner in 1925 (Photographer: Mustapha Abu el-Hamd, August 25 1926) (B) Bracelets in restored frame, Cairo JE 53271–3 (Photographer: Mohammedani Ibrahim, August 11 1929) (C) A bracelet (right) in the Museum of Fine Arts, Boston, MFA 47.1700. The bracelet on the left is an electrotype reproduction made in 1947. Sowada et al. (2023).

The bracelets donated to the Museum of Fine Arts were not available for study, but Sowada et al. were able to access the fragmentary material given to the museum at the same time. These samples were analysed using X-ray fluorescence spectroscopy to analyse their elemental composition. Furthermore, trace amounts of lead recovered from the sample were anlalysed using Multicollector Inductively Coupled Plasma-Mass Spectrometry, in order to determine their isotopic composition, which is strongly linked to geogrsphical origin.

(A) Bag B1 of corroded bracelet fragments in the Museum of Fine Arts, Boston, MFA 47.1702. MFA 47.1702 B1P4 shown second from left, centre. (B) Detail of MFA 47.1702 B1P4 (C)–(D) Metallic fragment recto (left) and verso (right) MFA 47.1702 B2P1. Sowada et al. (2023).

Sowada et al. found that the bulk sample of metal fragments was 98% silver, with 1% gold, 0.4% copper, and 0.04% lead. Patches of corrosion are dominated by silver chloride. Some other elements appear to have accumulated on the surface of the sample, notably calcium, but also iron, probably in the form of iron oxide grains. Examined under an a scanning electron microscope, fragments of the silver seen in section showed a pattern of dark and light layers typical of metal which has been worked heavily while cold, something often seen in Old Kingdom copper samples. Mapping of the elements in these profile sections suggested that the material was in fact about 90% silver and about 10% gold.

(A) Back-scattered electron image of part of the polished cross section from MFA 47.1702 B2P1 (B) Detail from image A at higher magnification, showing the metal structure to consist of elongated islands of uncorroded solver metal ('A') intercalated with a more porous matrix ('B') transitioning to an open framework of corroded metal ('C'). (C) Concentrations of silver and gold in small regions (purple outlines) were determined and plotted in (D). The plots begin at the top of the area shown in (C) and end at the bottom. The final data point is for the larger rectangular area and can be considered the average for this part of the sample (about 89% silver and 9% gold). Note that gold has higher concentrations and silver lower in the more heavily corroded areas (data points in the middle of the plots). Sowada et al. (2023).

The lead within the samples was found to have a lead²⁰⁶/lead²⁰⁴ ratio of 18.8816. This was compared to a database containing the isotopic rations of lead ores from 7000 locations between Iran and the Atlantic Ocean. This analysis susgests that the silver is most likely to have come from the Cyclades Islands, in the Aegean Sea to the southeast of the Greek mainland, and that the second most likely point of origin is the Lavrion mines of Attica. 

Map of the north-east Mediterranean and western Asia, showing potential silver sources. The lead isotope composition of a sample from MFA 47.1702 B2P1 is compared with the compositions of nearly 7000 samples of galena (white dots) distributed from the Atlantic Ocean to the Indian Ocean from the Ecole Normale Supérieure de Lyon database. The distance (colour bar to the right) allows 128 galena samples with the closest lead isotope compositions relative to MFA 47.1702 B2P1 to be retained. Unlikely sources can be ignored. A black symbol colour indicates a high probability of provenance with the greatest density of ‘hits’ coming from Seriphos, Anafi, and Kea-Kithnos in the Cyclades, and to a lesser degree Lavrion. Red and orange symbols indicate less probable sources (Anatolia, Macedonia). The symbol sizes have been slightly jittered and enlarged to increase visibility of the less probable points. Sowada et al. (2023).

Silver is known to have been mined in the Aegean region from the very beginning of the Bronze Age, and to have increasingly been traded around the Mediterranean as time passed; nevertheless, finding it as far afield as Egypt during the early Fourth Dynasty is surprising. Silver is known to have been imported to the Old Kingdom, with records dating to the reign of the Pharoah Sneferu mentioning the metal as an import, although not where it was imported from. The earliest records which do mention a source date to the late Sixth Dynasty (around 2300 BC), and record silver being imported from Byblos, in southern Lebanon. At the same time, records from Elba, in northern Lebanon, report silver being exported from that city to Egypt.

Heterpheres was the wife of Sneferu, who ruled 300 years before the Sixth Dynasty records were made, at a time when there is no direct evidence for trade between Egypt and Lebanon. A jug believed to have come from Cilicia in the Taurus Region of southern Anatolia is known from a slightly later tomb, suggesting that the Egyptians were trading this far north. This has been taken as evidence that Egypt could have traded silver from the cities of Lebanon, it is also known that silver from the Aegean was being traded in Anatolia by this time.

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Analysing silver from Phoenician hoards.

From about 4000 BC onwards the use of silver became widespread in the ancient world. This was obtained by smelting lead-ores in a furnace, and then cupellatiting (oxidising) the resultant metal to separate silver and gold. Lead ores, generally galena (lead sulphate) and cerussite (lead carbonate), were typically mined by a deep pit method, digging vertically down to a seem then following it horizontally. Silver  was important to many ancient peoples, among whom were the Phoenicians, who built city states such as Tyre, Sidon and Byblos, ‘Akko and Dor in Lebanon and on the northern shores of the southern Levant during the Iron Age, roughly from the eleventh century BC onwards, and who travelled widely on trading expeditions, bringing innovations such as the alphabet, murex-based purple dyeing and masterful craftsmanship to the western Mediterranean, where they established colonies in North Africa, Sardinia and Iberia. In the ninth century BC the Phoenicians began to exploit jarosite (potassium-iron sulphate) ores in Iberia, from which silver was also extracted as a biproduct.

Cupellation remained the most common way to obtain silver throughout the classical period, producing silver that still contains small amounts of lead. This is useful to modern archaeologists, who can use lead-isotope analysis to determine the source of silver. Other elements tend to be largely purged from the silver by this method, although gold and bismuth isotopes have sometimes been used to determine the origin of silver. 

Silverware was widely used as a trade commodity in the Near East before the adoption of coinage, with more than 40 silver hoards dating to between 2000 and 600 BC having been unearthed in the southern Levant.

In a paper published in the journal Applied Sciences on 12 January 2022, Tzilla Eshel of the Zinman Institute of Archaeology and School of Archaeology and Maritime Cultures at the University of Haifa, Ofir Tirosh of the Fredy and Nadine Herrmann Institute of Earth Sciences at the Hebrew University of Jerusalem, Naama Yahalom-Mack of the Institute of Archaeology at the Hebrew University of Jerusalem, Ayelet Gilboa, also of the Zinman Institute of Archaeology and School of Archaeology and Maritime Cultures at the University of Haifa, and Yigal Erel, also of the Fredy and Nadine Herrmann Institute of Earth Sciences at the Hebrew University of Jerusalem, present the results of a study which used lead and silver isotopes in silver artefacts to show changes in the source of silver reaching the southern Levant over a period of almost 1500 years, spanning the Bronze and Iron ages.

 

Map of the Southern Levant showing sites with Bronze and Iron Age silver hoards. Svetlana Matskevich in Eschel et al. (2022).

Examination of the lead isotope content of 250 silver items from 22 hoards suggests that Middle Bronze Age items (dating from between 2000 and 1550 BC), were made using silver from Anatolia and the Aegean. In the Late Bronze Age (from about 1550 to about 1250 BC), a time when gold probably replaced silver as the main trading currency, silver from the mines of Laurion (about 50 km south of Athens) begins to appear. During the Early Iron Age (roughly 1200 to 950 BC), following the end-Bronze Age collapse, silver appears to have been rare in the region, and was frequently adulterated with high lead content copper, making it hard to identify the origin of the artefacts. From about 950 BC onwards, Phoenicians revived the trade in silver, importing the metal from the Taurus mountains in Anatolia, and from Iglesiente in south-west Sardinia and later from the Pyrite Belt in Iberia, then from 630 BC onwards Greek traders slowly supplanted the Phoenicians, bringing in silver and copper from Laurion and Siphnos in the Aegean. 

This fits well with the previous understanding of the trade in sliver in the ancient Mediterranean Basin, but only gives a broad view of the geographic areas from which silver was being imported to the region; it does not shed any light on development of silver production practices and the exploitation of new ores. For this purpose, Eschel et al. turned to silver isotopes, which have a number of advantages in the tracing of the origin of ores. Silver will fractionate isotopically during supergene weathering; that is to say weathering caused by oxidation of minerals as water percolates through the rock in near surface environments, as well as during the formation of salts and sulphosalts. The upshot of this is that the proportion of different silver isotopes can vary even within different parts of the same mine, potentially giving a very high resolution way of determining the origin of the metal, and at very least, it is usually possible to tell the difference between silver minerals that formed in deep or shallow environments, with those that formed hydrothermally in shallow environments typically having a higher proportion of the heavier isotope silver¹⁰⁹ than those from deeper environments. 

This method has been applied previously to Hellenistic, Roman, and Medieval coins with some success, but not to pre-coinage silver hoards. As well as studying the origin of silver in Bronze and Iron Age hoards, Eschel et al. were able to study how the way in which the silver was preserved altered the isotopic ratio of the metal. It has previously been shown that the patterna on silver coins is isotopically lighter than the coins themselves, as the lighter isotope silver¹⁰⁷ is preferentially consumed in the making of silver sulphates. The silver from the Levantine hoards was stored in different ways, with some hoards stored in ceramic vessels, some in cloth bundles, and some in both, offering different levels of protection against intrusions by ground-water, which will tend to re-mineralise silver, altering its isotopic composition.

 

Silver hoards analysed in the study: (a) silver from the Shiloh hoard (without pendant), courtesy of the Israel Museum, Jerusalem. (b) Silver from hoard Tell el-‘Ajjul 1312, courtesy of the Israel Antiquities Authority. (c) The Dor silver hoard, the Israel Museum and the Tel Dor Expedition. (d) The ‘Akko silver hoard. (e) The ‘Ein Hofez silver hoard image courtesy of the Israel Antiquities Authority. (f) The ‘Arad silver hoard, courtesy of the Institute of Archaeology at Tel Aviv University. (g) Selected items from ‘Ein Gedi hoard, the Israel Museum, Jerusalem. Eschel et al. (2022).

Eschel et al. chose 45 silver artefacts for silver isotope analysis, all of known chemical and lead isotopic compositions and generally not suspected to be alloyed or mixed with metals from different sources. 

The oldest of these items came from the Middle/Late Bronze Age transitional period (roughly 1650-1500 BC) sites at Shiloh on the West Bank and Tell el-‘Ajjul in the Gaza Strip. The precise origin of these hoards is unclear, but both have jewelery with Anatolian motifs and lead isotopic analysis has suggested that the silver came from Anatolia or the Aegean. Both hoards were found wrapped in cloth bundles.

Silver from the Iron Age (roughly 950-700 BC) hoards at Dor, south of Haifa on Israel's Mediterranean coast, and ‘Akko in the coastal plain region of the Northern District of Israel, have been shown to come from Iglesiente, on southwest Sardinia, and have been associated with Phoenician trading in Anatolia and Sardinia in the Iron Age. The Dor hoard was found wrapped in a bundle, then placed within a ceramic vessel which was covered by a bowl, the 'Akko hoard was simply placed within a ceramic pot.

Silver items from the Iron Age (roughly 950-700 BC) hoards at ‘Ein Hofez inthe Carmel Mountains of northern Israel and 'Arad in the Southern District of Israel, on the border of the Negev and the Judean deserts have been shown to contain lead from Rio Tinto in Iberia, although this is only provides an approximate location for its origin, since jarosite ores from several parts of Iberia are known to have been brought to Rio Tinto for processing with lead. Other items from the ‘Ein Hofez hoard contain lead from Linares and other parts of Iberia, with one item coming from Anatolia. 

The Late Iron Age (roughly 630-586 BC) hoard from ‘Ein Gedi, in Israel west of the Dead Sea, near Masada and the Qumran Cave, contains silver placed unbundled within a cooking pot, covered by a ceramic lamp under the floor of a room. The lead in this silver indicates that it comes from Laurion in Greece, suggesting that it was brought to the area by a Greek trader.

Combining the silver and lead isotope analyses strongly suggests that the Phonicean hoards of Dor, ‘Akko, ‘Ein Hofez and Arad contain silver from Sardinia, Iberia and Anatolia, while the Late Iron Age hoard from ‘Ein Gedi contains Aegean silver, and the earlier, Bronze Age hoards of Shiloh and Tell el-‘Ajjul contain a mixture of Anatolian and Aegean silver. The isotopic ratios of the silver items from Phoenician hoards showed predominantly ratios consistent with having come from hypogene ores, that is to say ores that formed deep within the Earth, which had not undergone significant weathering related isotopic fractionation, whereas the isotopic ratios seen in the earlier Bronze Age and later Greek hoards showed more fractionation, probably indicating that they came from shallower ores which had undergone some surface weathering. 

While all the samples used were taken by drilling into the items to extract silver free from corrosion, some of the items still showed signs of sliver chloride formation at the level from which the sample was taken. This is symptomatic of corrosion through exposure to chlorine ions in groundwater, indicating that these samples were less protected from the environment than other samples. This was found in items from the hoards from Tell el-‘Ajjul, ‘Akko, and ‘Ein Hofez. The silver from Shiloh, Dor, ‘Arad and ‘Ein Gedi were apparently better protected. 

Based upon these findings, Eschel et al. were able to make the following observations. 

Hoards sealed in ceramic vessels were predicted to be best protected against contact with the soil and groundwater within it. The hoards from Dor (which was sealed in a vessel and bundled in cloth, and Ein ‘Gedi, which was sealed in a vessel but not bundled, showed no signs of corrosion, and therefore were apparently protected as expected.

Hoards wrapped tightly within cloth bundles were predicted to be less well protected against groundwater, though it was likely that the silver in the middle of the bundle would be protected somewhat by the silver around it. This would include the hoards at ‘Arad, which was tightly bundled and placed within a ceramic vessel, and which showed no signs of corrosion, and Shiloh, which was bundled but not placed within a vessel, where again no signs of corrosion were found.

Hoards placed within unsealed ceramic vessels were thought likely to be less well protected against groundwater. This included the hoards from ‘Ein Hofez and ‘Akko, both of which showed signs of corrosion.

Finally, silver which was neither bundled nor placed in a vessel was thought to be at the greatest risk of corrosion due to contact with the soil and groundwater. This was the case only with the hoard from Tell el-’Ajjul, which again showed signs of silver chloride formation.

The hoards from Tell el-‘Ajjul, ‘Akko, and ‘Ein Hofez all showed greater isotopic fractioning, which was taken as a sign of the silver in them having come from shallow ore sources, where this could occur prior to the silver being mined. Eschell et al. also note that the silver from these hoards also appeared to be less pure, and suggest that these combined may be a sign that they have been altered after deposition by their original owners, rather than evidence of a different mining origin or smelting technique to the other material.

Eschell et al.'s findings suggest that native silver (silver found in a pure state, which typically comes from deep, hypogene sources) was quite rare in the ancient world, and that most of the silver used came from shallow, supergene sources,

The Phoenicians are known to have brought silver to the Levan from the mid-10th century BC onwards, and from Iberia during the ninth and eighth centuries BC. It is unclear whether the Phoenicians themselves were the drivers of the improving metallurgical techniques being used in the areas where they traded, or whether they were just skilled traders able to aquire this silver and ship it across the Mediterranean. Anatolia is known to have been major centres of silver production from about the third millennium onwards, but the amount of silver being exported appears to have rapidly grown during the Phoenician era. Silver confidently assigned to a Sardinian origin is often found in Phoenician hoards, but no ancient mineworking have been discovered in Sardinia, so it is unclear when mining started there. Silver extracted in Iberia, in contrast, appears to have been exclusively developed by the Pheonicians, who targeted deep, low-lead ore bodies in the Iberian Pyritic Belt from about 800 BC onwards. The Romans began exporting silver from Iberia around 200 BC, but only targeted shallow ores with silver isotope fractionation, not the deep ores the Phoenicians were able to access.

The low levels of isotope fractionation seen in Phoenician sliver objects from Anatolia and Sardinia suggest that the Phoenicians were using the same deep-mining methods there in the tenth century BC, indicating that these people were more than talented sailors, but skilled workers in other fields, capable of transfering skills from one end of the Mediterranean to the other.

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