Seminar report: "Rome's most northerly frontier: the Antonine Wall"

On Thursday 12th February 2015, the Archaeology Society welcomed Prof. Bill Hanson from the University of Glasgow for an insightful talk about the Antonine Wall, Rome’s most northerly frontier in Scotland. After explaining the political context that triggered the building of the wall, Prof. Hanson went on to present the wall’s layout and organisation, drawing comparisons with Hadrian’s Wall further south, and the vallum Traiani, a linear frontier fortification built on the Danube in the 2nd century AD. Prof. Hanson also considers the Roman notion of "frontier" and the way imperial rule extended beyond the physical linear barrier of the walls. Throughout his talk, Prof. Hanson used a variety of evidence ranging from epigraphy to excavations, numismatics and ancient sources, showing the archaeological wealth of this period of the past. 

Source: Scottish Archaeological Research Framework. More on the Antonine Wall here.

The Antonine Wall crosses Scotland at the level of the firth of Forth, it is some 37 miles long and takes its name from the emperor Antoninus Pius, who reigned from AD138 to AD 161. The construction of the wall started soon after his accession to the throne. At the time, Hadrian's wall (built during the reign of the previous emperor, Hadrian) was still being built. The wall was however abandoned and the frontier line moved further north, into modern-day Scotland. The reason for this choice needs to be considered within the wider imperial context of the time. In order to stay in power - and to stay alive! - Roman emperors needed the support of the army, something which required them to have some military experience. Upon accessing the throne, Antoninus Pius had none. His campaigns in Britain to "conquer" the lands north of Hadrian's Wall gave him an easy victory and the support from the troops. A series of coins was minted in AD 142-144, hailing the emperor as being "twice" Imperator. (Roman emperors received the title imperator upon accessing the throne, and then again for every major military victory). In addition to the British campaigns, Antoninus Pius also moved the German frontier by about 24km and built part of the Limes (the line of fortifications along the eastern frontier of the Empire). 

Source: Wikimedia

Whereas Hadrian's wall was eventually built in stone, the Antonine wall is a turf rampart, of which relatively little survives nowadays as a result of its being located in the most densely populated area of Scotland. It is erected on a cobble base with draining channels. We do not know how high it was initially, it survives best at Rough Castle with an elevation of 1.5m. The most prominent feature surviving to this day is the ditch in front of the wall, which is some 40ft wide and 15ft deep. Along the line of the wall, a number of forts were erected. Unlike at Hadrian's Wall, were the forts were initially built behind the wall (and then relocated on the wall), the forts on the Antonine Wall were primary and part of the overall construction plan. They were built ca. 8 miles apart. In addition to forts, some fortlets were also built, as the equivalent of the milecastles on Hadrian's wall. However, the full sequence of forts and fortlets is not known as they do not always survive, many of them being turf and timber structures. At Rough Castle, cippi survive in front of the wall: they are small pits, closely packed together, which contained bushes and acted as a sort of Roman "barbwire line" (as opposed to the lilia, which contained stakes or metallic spikes and were, as Prof. Hanson put it, more like the Roman equivalent of a "mine field").

Cippi at Rough Castle

Other features of the wall are less well understood. For instance, a series of small enclosures exist, whose function we do not know and only one has been dug. Another enigmatic feature are the so-called "extensions",which occur in pair and are perhaps part of the signalling system of the frontier.  Like Hadrian's Wall, the Antonine Wall was not built according to one single plan: we see dramatic changes during the construction process.  For instance, extra forts were added, spaced by only 2 miles. At Croy Hill, a fort was added only 80m from a fortlet - primary, ie. built at the same time as the wall. Why build them so close together? We need to consider the wider socio-economic impact of the wall. Drawing a parallel with the Berlin Wall, Prof. Hanson explained how the construction of such a physical barrier would have disrupted the lives of native communities both in terms of social relationships and trading. A hostile reaction from the locals may have followed, thus triggering the reinforcement of the frontier with extra forts, and defence mechanisms like the cippi  mentioned above. A hint for this can be glimpsed through some of the depictions of the time. Unique in the Roman world are the so-called "distance slabs", recording which legions or units worked on the contruction of the Antonine wall, and which lengths of it they built.Some of these slabs are decorated by carved scenes, some representing captive "barbarians", a stock-motif of Roman imperial imagery (see for instance similar carvings from Gaul or Germany).

The wall in its wider context 

Finally, Prof. Hanson gave us some insight into the Roman view of their frontier. Beyond the Antonine wall, a series of outpost forts existed, as far north as Perth, where the fort of Bertha stood. The wall itself was not the frontier: imperial control expanded beyond it. There were however different levels of control and linear barriers such as the Antonine or Hadrian's wall were built to increase the level of control and the intensity of security. The vallum for instance, a large ditch behind (south of) Hadrian's wall, had not a defensive function but it was probably there to demarcate a military zone. The has been a long debate on whether or not Hadrian's wall was defendable: was there a walkway on the wall, like on a mediaeval castle? Maybe. But considering the length of the wall, the number of soldiers needed to defend it would have been too big. Furthermore, there was no need to defend the actual wall, when watch towers were built at very regular intervals, where legionaries could see possible assailants from afar. It seems that neither Hadrian's or the Antonine wall were meant to defend the Empire against major incursions. We do have evidence from Hadrian's wall of forts being destroyed by attacking forces from the north. The walls were however, efficient in repelling small-scale attacks. We do have an inscription from the eastern frontier, on the Danube, which records the building of the wall there in order to prevent small raids and thefts.

The Antonine wall does not seem to have been occupied after the 2nd century, with, among other sources of evidence, the latest date coin being from AD164-169. An inscription from Hadrian's wall records its refurbishment in AD 158. How this relates to the abandonment of the Antonine Wall is debated but in any case, what is sure is that the withdrawal from the Antonine wall was a deliberate one. It was dismantled and buried (this explains for instance, why the distance slabs are so well preserved). At Barhill, a well was found that was full of building material from the fort (including a column!). The exact reason behind the abandonment of the frontier is unknown. Some argue that it was a Brigantian revolt (the tribe living just south of the wall). What is interesting however, is that this abandonment coincides with the years surrounding the death of Antoninus Pius (AD 161): the wall had been his monument, it was no longer such a necessity once the emperor was dying. And so the troops were brought back to the first wall, Hadrian's wall.

The Society would like to thank Prof. Hanson for such an interesting seminar and wishes him the best of luck for his official retirement in September.

By Alexandra Guglielmi