When was Hadrian’s Wall built?

We know that Britain experienced tumultuous events during Hadrian’s reign. What we do not know is the order in which they played out. The answer may hold the key to understanding Britain’s premier Roman monument, as Matthew Symonds explains.

He came, he saw, and he built a wall, according to the Historia Augusta (HA). In AD 122, Hadrian (r. 117-138) became only the second serving emperor to visit Britain. We are told that he ‘corrected many abuses and was the first to build a wall, 80 miles in length, which was to separate the barbarians from the Romans’. On the strength of this report in the HA, which was probably compiled more than 200 years after Hadrian’s death, 2022 is the 1,900th anniversary of not only the emperor’s excursion to Britain, but also the order to erect the most famous monument to bear his name. While the traditional start date of 122 is still commonly used – and is also the basis for a welcome series of events commemorating the frontier – specialists are increasingly cautious about where precisely the decision to build the Wall falls amid the events besetting Britain during this era. A different start date could have important implications for how we view the Wall.

What’s in a year?

It is clear that Britain experienced violence at around the time of Hadrian’s visit. The HA notes that ‘the Britons could not be kept under Roman sway’ following Hadrian’s accession. Other straws in the wind include an expeditio Britannica or military taskforce being sent to Britain with 3,000 reinforcements, a tombstone from Vindolanda fort – just south of Hadrian’s Wall – referring to the death of a centurion ‘in war’, and the arrival of a new legion, the VI Victrix. Decades later, a correspondent of the emperor Marcus Aurelius (r. 161-180) used Britain during Hadrian’s reign as an illustration of severe Roman troop losses. That at least some of this turmoil is relevant to understanding the origins of the Wall is indicated by an inscription fragment found reused at Jarrow. The reconstructed text, which may once have graced a victory monument at Wallsend, states that ‘after the barbarians had been dispersed and the province of Britain recovered, he [presumably Hadrian] added a frontier line’.

LEFT Hadrian’s Wall is a remarkable relic of Roman military engineering, but what can we learn from the date when work started on it?
Hadrian’s Wall is a remarkable relic of Roman military engineering, but what can we learn from the date when work started on it?

One of the challenges facing Wall specialists is trying to set these events in chronological order. Perhaps the greatest unknown is the date of the expeditio Britannica. Many years have been proposed, but – as the late Anthony Birley observed – an emperor would normally be personally present. That makes 122 the most likely candidate, because Hadrian was in Britain. On the face of it, this allows a promising scenario to be proposed: the hostilities noted at the beginning of Hadrian’s reign were brought to a close by an expeditio in 122, after which order was restored and the Wall built. This fits nicely with diplomas issued to retiring veterans on 17 July 122. An unprecedentedly large number of military units in Britain discharged troops then, perhaps because terms of service had been extended to quell a preceding crisis. The diplomas also name Aulus Platorius Nepos, the new governor of Britain, who appears on building inscriptions from the Wall. By this reading, the Wall could be a broadly successful expression of Hadrian’s devotion to – as the HA put it – ‘maintaining peace throughout the world.’

above A well-preserved stretch of Wall curtain on Walltown Crags, which lies between the forts at Great Chesters and Carvoran.
A well-preserved stretch of Wall curtain on Walltown Crags, which lies between the forts at Great Chesters and Carvoran.

As has long been appreciated, though, it seems likely that there was an earlier cessation of fighting in Britain. A Roman victory c.119 would fit with coin issues of around that time featuring Britannia and destined for circulation in the province. A programme of road-building was also under way in 119-121. Both initiatives make sense as measures to aid post-conflict reconstruction. Most significantly, Erik Graafstal has recently made a case for several elements of Hadrian’s Wall being completed prior to Hadrian and Nepos’ arrival in 122. That would most likely require building to be under way in 121, while the preparatory work of planning, surveying, troop movements, and logistics could easily have taken a year or two, potentially pointing to a decision being made c.119. But if a victory was achieved then, how do we explain the need for an apparent expeditio in 122, and the quantity of units discharging veterans in the summer of that year?

This has raised suspicions of a second war. If so, a strong possibility is that rather than Hadrian’s Wall restoring order, work on the barrier system brought violence to a head once more. We know that it cut through a well-populated region, meaning that local political, working, and religious landscapes would all have been fractured. The Wall has also been implicated in the collapse of a long-standing agricultural community, which lay to the north on the Northumberland coastal plain (see CA 277). Local groups living nearby had plenty to lose, then, providing a powerful motive for resistance.

What this boils down to is that a start date in 122 could see the Wall helping to usher in a period of relative stability, while work commencing in 121 seems a better fit with it provoking an eruption of violence. Here, in its starkest sense, is the conundrum facing modern scholars seeking to understand the initial impact of Hadrian’s Wall: war or peace?

Further information
For more information about the 1,900th anniversary commemorations, visit https://1900.hadrianswallcountry.co.uk.
Matthew Symonds is the author of Hadrian’s Wall: creating division (Bloomsbury, 2021).