How to find your outpost on the Roman frontier

While the ancient names of many major Roman military bases are known today, it is less clear how smaller posts were distinguished. What steps did the authorities take to ensure that orders, post, goods, relief parties, or reinforcements were sent to the right place? David Breeze, Christof Flügel, Erik Graafstal, Simon James, Matthew Symonds, and Andreas Thiel investigate.

The study of Roman place-names has a long and respectable history, though littered with erroneous and strange identifications. Today we are generally agreed on the locations of the places listed in our ancient sources, though some defy identification. The military sites that we have ancient names for are largely frontiers, fortresses, and forts, but the Roman military also made use of much smaller installations, such as fortlets and towers. How were they referred to?

ABOVE A reconstruction of the fortlet at Pohl in Rhineland-Palatinate, Germany, a typical small military installation holding anywhere between 40 and 80 soldiers; the ramp is to enable wheelchair access. Such posts are widely found in the frontier zones of the Roman Empire, but how did contemporaries distinguish between them?
A reconstruction of the fortlet at Pohl in Rhineland-Palatinate, Germany, a typical small military installation holding anywhere between 40 and 80 soldiers; the ramp is to enable wheelchair access. Such posts are widely found in the frontier zones of the Roman Empire, but how did contemporaries distinguish between them? Photo: Jürgen Obmann, Bayerisches Landesamt für Denkmalpflege, Munich

To take Hadrian’s Wall as an example, we know the names of its forts from a combination of literary sources, inscriptions, and even ‘souvenir’ pans referring to these military bases. But if a soldier was outposted to one of the approximately 160 turrets along the Wall, how did he know how to find it? If a civilian was commissioned to deliver goods to one of about 80 adapted fortlets known as milecastles, what information was available to ensure that he or she went to the right one? More significantly, in the face of a threat to a frontier, the officer in charge had to deploy his men, and these soldiers required clear instructions about which sites to protect. Did fortlets/milecastles, towers, and other kinds of outposts have names, or numbers, or some other form of identification?

BELOW This view of the fortlet at Al-Heila in the Eastern Desert of Egypt emphasises how
This view of the fortlet at Al-Heila in the  Eastern Desert of Egypt emphasises how smaller  military installations might be difficult to find. 
Photo: Michel Reddé

This is not an arcane question, but strikes at the heart of how frontiers might have operated, and the answer is more subtle than a ‘one-system-fits-all’ approach. Many fortlets stood by themselves, filling a need in the landscape where an auxiliary fort was not required. But a frontier line or a frontier zone consisting of forts (occupied by different sizes and types of troops), fortlets/milecastles, and towers was an altogether different matter. Here, the officers in the ‘response centres’ – that is, the forts – would have to know the names or designations of the installations they were responsible for. On Hadrian’s Wall, it is possible that we can see a devolved structure through which orders were cascaded. The forts were about 11km apart, but at every mile there was a milecastle and between each there were two towers. Archaeological evidence suggests that soldiers did not permanently live in the towers: items of furniture and box fittings are not found there, but are recovered from forts and milecastles. In these circumstances, the milecastle might have had a name and towers identified in relation to it with the addition of ‘east’ or ‘west’.

The evidence for names

The space allocated to the smallest complete auxiliary unit in the Roman army, a 480-strong force, was about 1.2ha (3 acres). We know the names of most forts. We also have some evidence that smaller installations had names. One such place on Hadrian’s Wall was Drumburgh, which lay towards its west end and covered 0.8ha (a little less than 2 acres). Its name – according to the late Roman document, the Notitia Dignitatum – was Congavata, though the recently discovered 2nd-century Ilam Pan records its name as Coggabata. Elsewhere, Ellingen lies on the Raetian limes (‘limes’ being the Latin term closest to the English word ‘frontier’) in Germany. It is slightly smaller than Drumburgh at 0.7ha. An inscription records its name as Sablonetum. The name means ‘sandy place’ or ‘sandy soil’, which fits very well with its location. Coggabata may mean ‘scooped-out’, which would also fit its location well.

LEFT The relationship between the ‘response centres’ and the milecastles and turrets in one sector of Hadrian’s Wall. BELOW A detail of the inscription from Ellingen, with the
The relationship between the ‘response centres’ and the milecastles and turrets in one sector of Hadrian’s Wall.
Image: Erik Graafstal

We know of another small military installation named in relation to its location, Krokodilo/modern El-Mweih in the Eastern Desert of Egypt, which was probably named after an adjacent rock formation. No doubt, other military outposts were named after local features. Over 70 fortified sites have been identified in this desert, all below 0.92ha in size. One of the largest sites was Apollonus Hydreuma/Wadi Gemal on the Coptos–Berenike route. Despite their modest size, each post had a commander, as illustrated by one ostracon (a fragment of pottery bearing writing), which records an instruction from a centurion to those in charge of the installations: ‘Quintus Accius Optatus, centurion, to the four curators [commanders] of the praesidia [posts] along the via Claudiana, greetings. Let Asklepiades pass.’ Names are known for several of these desert posts. As well as the suggestively shaped landscape feature apparently referenced by Krokodilo, the desert posts could also be named after individuals, either mortal or divine. An example of the former is Maximianon, which presumably honoured a Maximianus or Maximus. Another small post is known as Dios/Iovis, thereby invoking Zeus/Jupiter, the patron deity of the fortlet. There are other examples of this approach, including nearby Didymoi, which was named for the Dioscuri.

A detail of the inscription from Ellingen, with the name SABLONETUM on the second line down.
Photo: Römermuseum Weissenburg; photograph Sabine Hegewald

Papyrus records of the 1,000-strong auxiliary regiment, the 20th Cohort of Palmyrenes, based in the city of Dura-Europos on the river Euphrates, specify that both infantry and cavalry were outposted to multiple places at least 100km upstream and 150km downstream. The documents are fragmentary, but record that most detachments contained only three to 11 soldiers, although the larger two comprised 63 and 93 men. The largest was based at the fortified settlement of Becchufrayn/Kifrin, well down the Euphrates from Dura, in modern Iraq. The second largest was on the river Khabur at Appadana. The name means something like ‘royal hall’, suggesting at least an origin as a Persian or maybe Parthian official station of some kind. One of the smallest detachments was based at Castell[um] Arab[um], presumably a military post of some nature, but others were based at villages, including the unlocated Avira, presumably billeted in local houses.

The fortlet of Iovis in the Eastern Desert of Egypt, guarding the route to the port of Berenice on the Red Sea.

North Africa provides a few examples as well, including Tisavar/Ksar Rhilane and Bezeros/Bir Rhezene in Tunisia. These both date to the late 2nd century and lie on the edge of the Great Eastern Erg, an area of sand dunes. Here the fortlets supplement the forts such as Remada/Tillibari and Cidamus/Ghadames. The Roman frontier zone in modern Tunisia and Libya was protected by small stone fortifications known as centenaria, some dating to the 3rd century AD. The names of some are known, such as the centenarium Tibubuci/Ksar Tarcine.

LEFT The locations of detachments of the 20th Cohort of Palmyrenes large at Appadana and Becchufrayn, and small elsewhere outposted
The locations of detachments of the 20th Cohort of Palmyrenes large at Appadana and Becchufrayn, and small elsewhere outposted.
Image: Simon James

There is evidence from the frontiers in Europe, the Middle East, and North Africa that small military outposts were named. This is hardly surprising, as soldiers would have to have such information in order to operate effectively in the frontier region. The Vindolanda writing tablets provide strong evidence for the importance of knowing the location of places in everyday life. Letters criss-crossed the northern frontier, recording communications with Catterick, about 80km distant from the fort, as well as the more local Coria/Corbridge and Luguvalium/Carlisle. The location of one place, Briga, is not known: it is usually assumed that it was a fort, but could it be one of the smaller installations in the frontier zone that escaped the attention of the scribes or was later abandoned?

The evidence for numbers

Writing tablets found at Vindonissa/Windisch in Switzerland show that houses within the legionary fortress were numbered. One writing tablet (35) records Valerius, shield-maker in house number 8, while at number 30 (tablet 38) was a custos armorum (keeper of the weapons). One writing tablet (47) states, ‘Think of your hostess in house number 12’; it is left to our imagination to decide who exactly was the hostess. Next door, at number 13 and perhaps not unconnected with the hostess, was the wine trader. A tile found at the fortress bearing the name ‘C OCTAVIUS’ has been interpreted as a name-plate.

Nor is Vindonissa unique. At Vindolanda, beside Hadrian’s Wall, fragments of wooden doors bearing the numbers III and XIV have been found in a barrack-block dating to the early 2nd century.

The names of officers

A third possibility is that outposts could be named after the officer in charge. The Dura rosters, for example, show that the centuries and troops in the 20th Cohort of Palmyrenes were named after their centurions and decurions rather than being numbered, while items of military equipment sometimes bear the name of a soldier and his centurion as a record of ownership. About the year 100, Masclus – a decurion – wrote from his outpost to his commanding officer at Vindolanda seeking instructions and asking for more beer; the outpost is not named, and there is an implication that it was ‘his’.

The fortlet at Tisavar/Ksar Rhilane in Tunisia. The site was well chosen and used by the French Foreign Legion in the Second World War.
The fortlet at Tisavar/Ksar Rhilane in Tunisia. The site was well chosen and used by the French Foreign Legion in the Second World War. Photo: Christof Flügel

This form of identification for an outpost might seem less helpful than a place-name, but not impossible to envisage owing to the Roman army’s well-known detailed recording system. Could Maximianon in the Egyptian Eastern Desert be named after its first commander, or perhaps someone involved in its genesis? While this was a longstanding post, commanders might also have lent their names to outposts judged likely to be temporary. Nor should we forget that sometimes a regiment gave its name to its base, an example being Commagena/Tulln in modern Austria, named after the ala I Commagenorum.

LEFT Parts of two wooden doors found in a barrack-block at Vindolanda, bearing the numbers III and XIV. They date to the first two decades of the 2nd century. BELOW One of the writing-tablets at Vindonissa recording a house number: ‘For the custos armorum [keeper of the arms] in house number 30.’ The number is indicated by ‘XXX’
Parts of two wooden doors found in a barrack-block at Vindolanda, bearing the numbers III and XIV. They date to the first two decades of the 2nd century.
Photo: Vindolanda Trust
One of the writing-tablets at Vindonissa recording a house number: ‘For the custos armorum [keeper of the arms] in house number 30.’ The number is indicated by ‘XXX’. Photo: Kantonsarchäologie Aargau; photograph Béla Polyvás

The answer to the tantalising question, ‘Did the milecastles and turrets on Hadrian’s Wall and the fortlets and towers on the German frontier and elsewhere have unambiguous identifications?’ is surely ‘Yes’. Fortlets certainly had names, and the numbering of houses in the legionary fortress at Vindonissa, and possibly rooms at Vindolanda, strongly suggests that towers might have had numbers. While the triplet of tower-milecastle-tower on Hadrian’s Wall may point to the use of ‘east’ and ‘west’ in relation to the milecastle, the occurrence of greater numbers of towers between the fortlets on the German frontiers indicates that here simple identifications like ‘east’ and ‘west’ will not do. It may seem unlikely that the towers were numbered from one end of the frontier to the other, but perhaps they were numbered in relation to individual forts or fortlets. A further complication is that we do not know how the soldiers outposted to the towers on the British and German frontiers were supplied, nor how frequently they were relieved. Some of the soldiers sent out from Dura stayed at their posts for at least three years; at the other end of the scale, a soldier in the Egyptian Eastern Desert gave thanks for a five-month posting. Shorter-lived outposts might be named after the senior officer present. Perhaps the discovery of further writing tablets will answer the question.

FURTHER READING
D J Breeze, The Frontiers of Imperial Rome (Barnsley, 2011).
M Reddé, Les frontières de l’Empire romain (Lacapelle-Marival, 2014).
E Krieger, Die Wachttürme und Kleinkastelle am Raetischen Limes (Limesforschungen 30; Berlin, 2019).
M A Speidel, Die römischen Schreibtafeln von Vindonissa: Lateinische Texte des militärischen Alltags und ihre geschichtliche Bedeutung (Veröffentlichungen Gesellschaft Pro Vindonissa 12; Brugg, 1996).
A K Bowman and J D Thomas, The Vindolanda Writing Tablets: Tabulae Vindolandenses II (London, 1994), Tabulae Vindolandenses III (London, 2003).