Saturday 9 October 2021

Grociana piccola: A fortification in northern Italy dating to the Roman Republic.

The Roman Republic saw the first expansion of Rome as a military power capable of dominating other areas of the Mediterranean, and the development of the distinctive military system which enabled the Roman Empire to dominate much of the world they knew. This makes the Roman military of this period of particular interest to archaeologists and historians. However, surprisingly few Roman fortifications survive from this period, with most of those that do being on the Iberian Peninsula, which may not, therefore, represent an accurate picture of the wider Roman world. Recently, investigations around Trieste, in northwestern Italy, have uncovered a series of military fortifications dating to the Roman Republic. These military fortifications are arranged in a linear pattern, facing towards northern Istria (a peninsula at the northern end of the Adriatic, and are thought to date from the Second or Third Istrian Wars (the conflicts in which the Romans subdued the peoples of Istria, whom they deemed to be 'fierce pirates'). Three fortifications have been found to date, a main camp on San Rocco Hill, and two smaller camps flanking this main fortification, Montedoro to the southwest and Grociana piccola to the northeast. San Rocco appears to have been occupied from the early second century BC till some time in the first century BC, while material excavated at Grociana piccola suggests this site was occupied between the end of the second century BC and the middle of the first century BC, although these sites may not have retained their military significance throughout their occupation history. 

In a paper published in the Journal of Roman Archaeology on 20 September 2021, Federico Bernardini of the Department of Humanistic Studies at the Università Ca’Foscari, and the Multidisciplinary Laboratory at the 'Abdus Salam' International Centre for Theoretical Physics, Jana Horvat of the Inštitut za arheologijo, Giacomo Vinci of the Dipartimento di Matematica e Geoscienze at the Università di Trieste and the Multidisciplinary Laboratory at the 'Abdus Salam' International Centre for Theoretical Physics, Tina Berden and Lucija Lavrenčič, also of the Inštitut za arheologijo, Lucia Liccioli of the Sezione Firenze at the Istituto Nazionale di Fisica Nucleare, and Carmine Lubritto of the Dipartimento di Scienze e Tecnologie Ambientali Biologiche e Farmaceutiche at the Università della Campania 'Luigi Vanvitelli', present the results of a series of field walking exercises and small investigations at Grociana piccola, carried out between 2016 and 2019, and discuss how these results relate to Roman military expansion in the northwest Adriatic region, and the evolution of Roman military architecture.

(a) Position of the investigated area; (b) location of the Trieste fortifications. Bernardini et al. (2021).

The Grociana piccola fort is located on the Trieste Karst Plateau, overlooking Muggia Bay and sea and land routes connecting Aquileia, Istria, the area that makes up modern Slovenia and the Gulf of Quarnero in modern Croatia, and is both visible from, and able to see, the larger Roman fortification at San Rocco. This would have given the site considerable strategic value, as well as the ability to exert control over sections of the Trieste Karst Plateau not visible from San Rocco.

A LiDAR (Light Detection and Ranging, a form of remote sensing method that uses light in the form of a pulsed laser to measure ranges) investigation of the site found the outlines of two structures, one within the other. The larger had a roughly trapezoidal shape, an east-west orientation, and an interior area of about 4000 m². The smaller outline, which lay completely within the larger one, being sub-rectangular, orientated roughly northeast-southwest, and had an interior area of about 2000 m². Ground inspection of the site suggests that the perimiters of these structures were simple earth banks. The outer perimeter had two clavicula entrances (areas where the surrounding rampart curved inwards to provide extra protection for a gate), on the north and east sides; it is possible that these were also originally present on the south and west sides, as having an entrance on each side was a standard Roman practice.

Schematic plan of the Grociana piccola fortifications with the position of trenches 1 and 2 and the archaeological finds. Gray circles: caliga hobnails; black triangles: pottery; white diamonds: other metal finds; white circle: Roman coin. Bernadini et al. (2021).

Much of the archaeological material recovered by Bernadini et al. was found during surface surveys. This includes a variety of pottery shards, including fragments of amphora (storage vessels), and pieces of smaller, thinner walled pottery items. Three rim fragments attributed to Lamboglia 2 amphora were found; these are thought to date to the late second or early first century BC.

A total of 96 hobnails were recovered from the site. These are thought to have come from caliga (boot-like sandels worn by lower ranking Roman soldiers). These range from 11 to 22 mm in length and from 3 to 8 g in weight. The majority (74) have a cross and four dots on their underside, four have numerous dots arranged in a circle, two have well spaced large dots, one has a cross but no dots, and eleven are unmarked.

Selection of metal finds from surveys at Grociana piccola. Andrea Fragiacomo in Bernadini et al. (2021).

The majority of the hobnails belong to the Alesia D type, which is best known from the Late Republic period, including the campaigns of Julius Caesar in Gaul and the early campaigns of Augustus, although it is likely that these nails were in use by the second century BC. The nail with the simple cross is assigned to the Alesia B type, also known from the Late Republic period, while those with circles of small dots probably date from the first century AD. The hobnails without marks, and those with large well spaced dots, could have come from almost any point in the Roman era.

Other metal objects were also found. These include a pointed, socketed object interpreted as part of a weapon, probably a spear or bolt. Such objects are common throughout the Roman era, though it should be noted that several similar items were found among a hoard of Roman Republic weapons found at Grad, near Šmihel in Slovenia, about 250 km to the northwest of Grociana piccola, which have been dated to the late second century BC. Also found was a simple iron rod, which might have formed part of an arrowhead, and which resembles examples from Grad, while another object appears to be a more unusual arrowhead. Another piece of metal is thought to be part of a shield binding, and an iron ring about 3 cm in diameter and an iron point are of less certain origin. Finally, Bernadini et al. found an 'as' (bronze Roman coin) dating to the early second century BC.

In addition to the surface surveys Bernadini et al. excavated two trenches. The first of these cut through part of the inner terrace and accompanying terrace. This trench exposed only dry-stone building materials, thought to have come from a rampart, and about 30 kg of pottery. The dry-stone structure was built onto the bedrock, which appears to have been close to the surface at the time of construction; a thin, ancient soil can be seen on the northern and southern sides of the rampart, but is only a few cm thick. The rampart itself is about 1.5 m wide at the base, being made up of two sloping walls of large blocks 40-50 cm across, with an infill of smaller stones, red sandy soil, and pottery fragments, between them. An additional wall of large blocks was found about 50 cm from the outer sloping wall, and the space between these walls was filled with brown soil, with occasional charcoal fragments. One of these charcoal fragments provided a radiocarbon age of between 196 BC and 86 AD.

Trench 1: inner rampart from northeast before the removal of tumbled blocks. Bernadini et al. (2021).

Inwards of the rampart, a natural depression in the bedrock contained pottery fragments, including 1398 pieces of amphorae, and pieces of smaller, thinner walled pottery, as well as a single hobnail. Bernadini et al. suggest this accumulation was deliberately laid down to create an even floorspace within the fort.

Part of the rampart has collapsed inward to the south. The debris at this area contains not just material that appears to be derived from the wall, but also 418 fragments of amphorae and three hobnails, which may suggest that the wall debris fell onto, and is mixed with material from, the living area inside the wall.

Trench 1: plan of the trench after the removal of the collapse layers, and east cross section. Gray circle: caliga hobnail; diamonds: registered ceramic fragments; gray symbols in SU 8: other registered and unregistered ceramic fragments; black circles: organic and inorganic samples. Bernadini et al. (2021).

The vast majority of the pottery remails found at the site (about 96%) come from amphorae. The majority of these are parts of the body of these containers, but eleven rims were found among the debris, giving a minimum number of vessels. The fragments are of light colours (reddish yellow, pale yellow, pink), which is typical of amphorae from the Adriatic region. Eight of the eleven rims can be identified as being of the Lamboglia 2 style, generally used to ship wines from the Italian Adriatic coast. This type of amphorae is considered to have evolved from Adriatic Greco-Italic Amphorae in the mid-to-late second century BC, and to have evolved into Dressel 6a Amphorae in the last three decades BC.

The Lamboglia 2 Amphora rims from Grociana piccola have a triangular cross section, which is typical of earlier vessels of this type. Three of the rims have smaller dimensions and a protruding triangular shape, which might indicate that they are of the late Greco-Italic Amphorae type; being notably similar to amphorae assigned to this type from Sermin, on the nearby Adriatic coast of Slovenia, although Bernadini et al. note that it is difficult to distinguish between late Greco-Italic and Lamboglia 2 amphorae. A wheel-thrown amphora lid was also found, although this could have conceivably fit either type of vessel. 

Selected amphora remains from trench 1. Tamara Korošec in Bernadini et al. (2021).

In order to estimate the age of the Grociana piccola amphorae, Bernadini et al. compared them to Lamboglia 2 Amphorae from Razdrto-Mandrga in Slovenia, dated to the end of the second century and beginning of the first centuries BC, Greco-Italic Amphorae from Sermin dated to the late third and early second centuries BC, and Greco-Italic amphorae from a kiln site in Cattolica, slightly to the south of Rimini on the Adriatic coast of Italy, dated to the end of the third century BC. They caried out a morphometric analysis using the angle between the horizontal line and the exterior of the sloping rim edge, the thickness of the rim at its greatest width, and the height of the rim from the point of the greatest width to the top. They found that amphorae from Grociana piccola with Lamboglia 2 rims were similar only to amphorae from the earlier phases at Razdrto-Mandrga, while those with Greco-Italic rims were comparable to both those from Sermin and those from Cattolica. Based upon this, they suggest that the Grociana piccola should be dated to the second century BC.

Other pottery recoverd from Grociana piccola is consistent with second century BC Roman manufacture. This includes a number of thin-walled beakers of the Marabini 3 form, which appeared in Tyrrhenian Italy in the early second century BC, spread around first Italy, and then the wider Medeterranean, then disappeared around the middle of the first century BC. Curiously only a single fragment attributed to a cooking vessel was found, part of a general lack of typical domestic waste at the site.

A total of four hobnails were recovered from this trench, three with the cross and four dots pattern, from the area with the collapsed rampart section, and one with circularly arranged dots, from the occupation layer.

(a) Selected pottery from trench 1; (b) metal finds from trenches 1 and 2. Tamara Korošec in Bernadini et al. (2021).

The second trench cut through the northeastern corner of the outer rampart. Again, this was made of two rows of large stones situated on a limestone bedrock, with a fill of smaller loose material. The bedrock appears to have been covered by only a thin layer of soil at the time of construction. Behind the curved rampart corner lies an inner sloped platform constructed from two further sloped walls made of larger blocks than the outer wall, but again filled with smaller stones. Bernadini et al. suggest that this might have served as the base of a tower or some sort of artillery platform. As with the inner rampart, sections of this outer rampart appear to have collapsed at some point.

Plan of trench 2 after the removal of the collapse layers, and west cross section. Gray circles: caliga hobnails; black circles: other metal finds. Bernadini et al. (2021).

Four hobnails were discovered in this section. Two of these were of the Alesia D type with a cross and four dots pattern; one of these was found within the rampart fill, the other on what is interpreted to have been the walking surface within the fort at the time of use. Both of the two remaining nails were also found on this walking surface; one of these had no markings, the other was too corroded to identify whether markings were present.

The inner rampart at Grociana piccola was made up of two sloping walls of large blocks, about 1.5 m apart at the base, with an infill of loose material. This wall is only likely to have been about a metre high when it was built. This structure seems crude when compared to modern expectations about Roman military architecture., but can clearly be identified as Roman by the pottery and other artefacts present. On the northern side, at least, a second stone wall lies about a metre outside this wall, which may has served as a support for some form of additional defensive wooden structure, with comparison to other Early Roman sites suggesting that this might be a raised walkway.

Similar three-walled ramparts have been uncovered at Roman forts in Numantia in modern Castile, Spain, but these have a third wall interior to the sloping ramparts, and slightly higher, whereas the example at Grociana piccola is external to the ramparts and slightly lower than them. A similar structure has been found at a Roman fort at Cáceres el Viejo in the Extremadura region of Spain, a site dated to between 82 and 72 BC, which has been interpreted as part of the base of the rampart.

The small size of the inner fortification, combined with the second century BC ceramics found inside and the strategic connection to the San Rocco fort strongly suggest that this structure would have been in use during the Istrian War of 178-177 BC, during which Rome conquered the Istrian Peninsula, and possibly later in the second century BC, although it probably lost its military value once the area was pacified.

The outer rampart was curved at its corners (or at least the northeastern one), with an inner wall that was probably no more than 1 m wide and 50 cm high, surrounded by an outer line of large stones. The area between these was infilled with lose stones, at the bottom of which a Alesia type D caliga hobnail was found; other hobnails, including another Alesia type D example, were found on the walking floor inside the wall. Just inside the northeastern corner of the platform a 2 m wide rectangular platform with a north-south orientation was found. This again has an infilling of smaller stones, and may have served as the base for a tower or artillery platform. The inner part of the wall and platform are likely to have been covered either by soil and turf or by wooden planks. It is likely that the area between the two walls held additional wooden defences.

Platform towers of the type seen at Grociana piccola would become a distinctive feature of Imperial-era Roman forts, but there are few Republican-era examples. Some examples are known from Renieblas and the Numantia region, but these are not at the corners of forts, and are not present at all sites. Caesarean camps appear to have lacked them altogether. Thus the tower-base at Grociana piccola appears to be an important early example of an important Roman military innovation.

Clavicula entrances of the type seen on the outer rampart at Grociana piccola are not seen elsewhere until the first century BC, and nor are the Alesia type D caliga hobnails found in the outer rampart. A coin of older origin was found within this perimeter, but such a coin circulating long after it was made would not have been unusual, so it is likely that the outer fortification dates to the first century BC. The absence of internal buildings, cooking materials, etc., suggests that this outer fortification was only used very briefly.

Republican-era Roman military fortifications are rare in Italy and the northern Adriatic region, making the Grociana piccola fort a significant find. The small size of the structure, combined with the likely date provided by the pottery within suggests it was a satellite fort associated with the nearby San Rocco camp. The period when this fort saw several conflicts in the region; the First Istrian War of 221 BC, a conflict with a migrating Celtic tribe in 183 BC, a smaller conflict with the Histri (Istrians) around the time of the founding of the Roman colony of Aquileia in 181 BC, and the final subjugation of the area in the war of 178-177 BC (which is variously described as the Second or Third Istrian War). A permanent garrison was established in the region in 176 BC, and involved in a series of conflicts with local tribes until about 115 BC. The Grociana piccola and San Rocco forts could have been used in any of these conflicts, as well as other events of which no records remain, although the war of 178-177 BC is the only one known to have had significant fighting this close to modern Trieste. The outer ramparts of the fort probably date to the first century BC, when the Romans fought a series of conflicts in the northern Balkan Peninsula, from about 78 to about 34 BC. Whatever the military significance of Grociana piccola, its architecture is clearly important, providing an early example of a type of construction later used at much larger Roman camps across the Empire. 

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.