Hadrian’s Wall: A Roman frontier revisited

How much do we really know about Hadrian’s Wall? After more than a century of scientific research into this magnificent Roman monument, it might be suspected that few mysteries remain. Instead, the recent ‘Pilgrimage’ along the Wall showed that debate is still in rude health, as Current World Archaeology's Matthew Symonds reveals.


In 1848, revolution stalked the streets of European cities. As mobs demanding political freedoms took up arms and manned barricades, few observers could have guessed that the events playing out on the Continent would prove pivotal for Hadrian’s Wall studies. This unlikely outcome can be credited to one man – John Collingwood Bruce – surveying the European powder keg and deciding to look elsewhere for his summer holiday. Bruce had been planning to travel to Rome, but with that hope scuppered by the unrest, he decided to inspect an antiquity that lay rather closer to home: Hadrian’s Wall. The ensuing expedition included Bruce, his son Gainsford, and two brothers, one of whom was a school art-master tasked with composing watercolour keepsakes of the trip. Over the following autumn, Bruce gave a series of lectures in Newcastle, using the watercolours to illustrate his talks. Some members of his audience reacted with consternation to the claim that such impressive Roman ruins lay on their doorstep. So it was that the following year, 1849, Bruce led a tour or ‘pilgrimage’ along the Wall, allowing the 24 participants to judge for themselves. A new chapter in the story of Hadrian’s Wall had opened.

Hadrian’s Wall, as it crosses the picturesque crags studding the central sector of its course. This majestic Roman frontier has attracted archaeological attention for more than a century, but many mysteries still surround the monument.

Bruce’s involvement with Hadrian’s Wall did not cease in 1849. The frontier had cast its spell over him and, by the end of Bruce’s life in 1892, he was the acknowledged doyen of Wall studies. In the intervening decades, he led a second sojourn along the Wall as ‘Chief Pilgrim’ in 1886, and did much to kindle public interest in the monument by writing a popular guide that became known as the Handbook to the Roman Wall. Remarkably, both of these innovations have stood the test of time. Modern visitors setting forth to explore the Wall will find that the Handbook is still an invaluable companion, albeit in its 14th edition, overhauled by David J. Breeze. Breeze is also, appropriately enough, the current Chief Pilgrim and has just published a history of these excursions (see ‘Further reading’ on p.40). Following that second pilgrimage in 1886, a tradition grew up of repeating the event every decade, breaking only for the First and Second World Wars. After the latter, the pilgrimage was rescheduled to 1949, allowing it to fall on the centenary of the first. The most recent Pilgrimage – the 14th – duly followed in 2019, when 211 Pilgrims participated in what the organisers believe is the oldest continuing archaeological tour in the world. As well as being charmingly convivial affairs, the pilgrimages offer an opportunity to take stock of where Wall studies are, and also look to the future. In that spirit, we will consider one longstanding line of enquiry here: what the Wall was initially intended to achieve.

John Collingwood Bruce, leaning on an altar dedicated to Jupiter Optimus Maximus. Bruce was planning to visit Rome in 1848, but, as insurrection spread across Europe, he turned to Hadrian’s Wall instead. It was a decision that changed the course of his life. Image: courtesy of David J. Breeze.

Given the increasingly ingenious scrutiny that Hadrian’s Wall has received since Bruce’s day, it might seem doubtful that there is much left to say about the monument. The truth, though, is that there are still major gaps in our knowledge of almost every aspect of the Roman frontier. Ancient authors had little to say on the subject, with the only clear statement of its role occurring in a document that was probably compiled more than 200 years after the barrier was built. This document, known as the Historia Augusta, discloses simply that Hadrian ‘was the first to build a wall, 80 miles in length, to separate the barbarians from the Romans’. At first sight that seems clear enough, but history – and indeed the modern world – is replete with examples of barriers, borders, and frontiers that apply very different degrees of separation, ranging from a near-total block on movement to little more than regulating daily transit. Even so, the passage in the Historia Augusta seemed to fit neatly with an obstacle that appeared – from surface inspection of the ruins – to present few opportunities for passage across the frontier, other than at forts. By the 19th century, it was perfectly mainstream to view the Wall as a cordon sanitaire screening off the Roman province from savage northern aggressors.

The near-silence of the ancient sources has left us heavily reliant on archaeology to test perceptions of Hadrian’s Wall. Indeed, the very first pilgrims in 1849 were able to inspect a spectacular example of how investigating the ruins could be an interpretative game changer. Local landowner and murophile John Clayton had tasked his workmen with exposing – ‘excavating’ would be too strong a word – the remains of one of the small posts along the Wall. These were positioned at sufficiently regular intervals to become known to locals as ‘milecastles’, and we now know that they probably held garrisons of around eight to 32 soldiers. In 1848, Clayton’s diggings yielded the discovery that the milecastle contained two entrances, one in its north rampart and one in its south. This meant that it was possible to cross Hadrian’s Wall within the milecastle. Further work at other milecastles followed, to test whether the arrangement was an aberration. Instead, it was established that a frontier gateway was a common feature of these posts. The vision of the Wall as an impenetrable obstacle vanished in the face of sizeable gateways positioned at approximately mile intervals. As David J. Breeze has noted, contemporary scholars were left to mull the implications of northern lands that had not been simply sealed off.

Bruce used watercolours of the ruins – including this one featuring himself and his son Gainsford in the Wall ditch at Limestone Corner – to illustrate a series of talks. His audience’s appetite to inspect the remains led to the first Pilgrimage in 1849. Images: courtesy of David J. Breeze.
Hadrian’s Wall, as it appeared at the end of Hadrian’s reign, after a series of forts had been added. For most of the Wall’s course a major watercourse flows directly to either its north or south, but an exception occurs in the narrow Tipalt–Irthing gap, lying to the west of Carvoran and east of Birdoswald.

More than 150 years later, these milecastle gateways remain an unresolved issue at the heart of debate about the Wall’s purpose. After all, understanding the nature of the separation that the Roman army sought to impose boils down to the question of who could pass through these gateways, and under what circumstances. This is reflected in current Wall studies, which revolve around two opposing views of the monument. One camp sees it as a measure to regulate the peaceful movement of people, while the other envisions a fortification capable of repulsing a full-blown barbarian invasion. Broadly speaking, the first model holds that civilians could use the milecastle gateways – doubtless after checks were made and taxes extracted – while the second sees these portals as a means to minimise the inconvenience the barrier posed to Roman military manoeuvring. By this second reading, civilian traffic would be restricted to the two or three points where major highways crossed the Wall, creating a considerable obstacle to movement. These different intentions speak of very different circumstances prevailing in the region when the Roman emperor Hadrian ordered the Wall’s construction. Either the region was broadly stable and measures were taken to minimise disruption to communities living to the north and south, or serious fears were entertained about a full-scale onslaught. What kind of a barrier, then, was Hadrian’s Wall?

Clayton’s workmen began unearthing this milecastle, on Cawfield Crags, in 1847. As work continued into 1848, it was realised that the milecastle contained two substantial gateways, permitting passage through Hadrian’s Wall.

Most of the books on the subject will tell you that work on the Wall started in AD 122. Hadrian was in Britain that year, so it seemed natural that he would have personally examined the situation on the ground, before giving orders for the Wall’s construction. Although there had been dissenters from this view, the argument that the Wall might have been created before Hadrian’s visit was rekindled by Erik Graafstal in 2012. Among the strands of evidence he wove together was the observation that work on a Roman frontier barrier in Germany seemingly anticipated the emperor’s arrival, presenting him with something to inspect. If work on the timber palisade forming the frontier in Germany was geared towards giving the emperor a taste of the finished work, it is easy to see how Hadrian would have been eager to preview the far more monumental works planned in Britain. Imperial curiosity aside, though, pushing the start date for construction earlier also brings it closer to upheaval recorded at the beginning of Hadrian’s reign, when we are told that ‘the Britons could not be kept under control’. As Graafstal pointed out, Roman inscription fragments found reused at Jarrow, near the eastern terminus of the Wall, hint at a similar possibility. The text has been reconstructed to state that ‘after the barbarians had been dispersed and the province of Britain had been recovered, he added a frontier line…’.

A schematic diagram showing the Wall as it was originally conceived (A) and after the decision to add a series of forts and the Vallum (B). The original concept was for an unusually regular cordon comprising milecastles and turrets, with larger garrisons held in forts to the rear. David J. Breeze and Brian Dobson have calculated that inserting the forts would place an additional 9,090 soldiers on or adjacent to the Wall. Image: after Breeze and Dobson.

If Hadrian’s Wall was built in the aftermath of bitter fighting, the temperament of the local Britons living in the broader region would surely have been a factor. That the Wall was constructed with a keen sense of the security situation seems implied by the details of its construction. Archaeological investigation has revealed that the original plan for the Wall was highly – indeed abnormally – formulaic. The design envisioned a regular sequence of milecastles, with two turrets at intervals of approximately ⅓ Roman mile between them, linked by a sturdy barrier.

Small turrets broke up the distance between neighbouring milecastles, resulting in manned posts approximately every 495m along the curtain. This example, at Caw Gap, was eliminated later in the Wall’s history. At around the time the forts were added, a monumental earthwork now known as the Vallum was cut to the south of Wall. It typically comprises a north and south mound, flanking a ditch about 6m wide, creating an obstacle around 35.5m across.

For about two-thirds of the Wall’s overall length, this barrier would take the form of a 3m-wide stone curtain, while for the remainder a turf rampart was raised. To the north, a ditch was cut where the crags did not render one redundant. Given the small numbers of troops available within the milecastles, any need for substantial reinforcements could only be met by forts lying to the south of Wall, in particular along a key highway known as the Stanegate. While construction was still under way, though, there seems to have been a sudden change of plan. A series of forts was added to the line of the Wall, sometimes at the cost of demolishing milecastles or turrets, while a massive 35.5m wide earthwork known as the Vallum was installed to the south. The reason for this departure from the original plan is unclear, but given that these forts held units ranging from just under 500 to over 1,000 strong, a deteriorating security situation might be suspected.

The Wall on Highshield Crags, with the South Tyne valley visible beyond. What impact did this barrier have on existing farming communities?

Sensitivity to local stimuli is also suggested by unpicking the order in which elements such as the milecastles were constructed. Fortunately for archaeologists, at around the time that the forts were added, the width of the stone curtain was reduced from roughly 3m to about 2.3m, allowing us to isolate those elements that were started first. This indicates that early work began on some milecastles blocking key existing routes through the landscape. In some places, these thoroughfares take the form of important valleys, such as that of the North Tyne; in others, they could plausibly have been approaches to fords that were certainly of significance in more recent centuries. One place that seemingly received both early milecastles and various measures that depart from what could be considered the ‘standard’ Wall template is the Tipalt–Irthing gap. The army’s willingness to be flexible in and around this natural junction in the landscape suggests that the gap was a point of particular concern. It presents a 2.55km-wide bottleneck between the Tipalt Burn and Irthing River, which marks the only place along the Wall where it is possible to travel north–south without also having to cross a major watercourse. The gap also acts as an interface between lowland and upland farming regimes, while a major pre-Roman shrine probably lay 9.6km to the north at Bewcastle. Blocking the gap would have disrupted seasonal interactions between pastoral and arable farmers, as well as pilgrims journeying to the shrine. It is only a short step from this to speculating that local communities’ dawning realisation about Roman intentions prompted a spike in resistance, which in turn led to the addition of Wall forts.

Looking west, as the Wall descends into the Tipalt–Irthing gap. The area in and around this 2.55km-wide natural bottleneck appears to have been a point of particular concern to the Roman military.

Warfare in the Wall zone is normally believed to take the form of set-piece battles between Romans and Britons. Surviving ancient histories, though, indicate that the Roman army in Britain was most commonly confronted – and confounded – by enemies engaging in what we would now call guerrilla or low-intensity warfare. Numerous features of Hadrian’s Wall appear well-calibrated to frustrate the kind of hit-and-run attacks favoured by fighters employing guerrilla tactics today. Such scenarios nudge us towards envisioning a barrier that was not straightforward for local groups to cross. Over recent decades, a growing number of Wall specialists have tended towards the milecastle gateways being primarily intended for military use. Geophysical survey in the environs of six milecastles by Altogether Archaeology has provided support for this. If milecastles acted as nodes for the routine movement of people, durable routes leading to them from the north might be expected. Instead, traces of potential – though undated – access tracks were only detected at one of the posts investigated

A sulphurous spring in the Irthing Gorge, just north of the Tipalt–Irthing gap. The spring lies on the grounds of the Gilsland Hall Hotel and, according to a leaflet for visitors, its waters were once reputed to cure ‘disease of the kidneys, gout, indigestion, lowness of spirits, consumption, skin diseases, ulcers and even worn-out constitutions’. One receptionist remembered that when she was little, the aroma of bad eggs emanating from the spring was so off-putting that her friends used to dare each other to drink the water. It certainly makes a memorable beverage.


If a hard barrier were suddenly imposed on the landscape, it might reasonably be expected to have had an impact on the farmers who had worked the region for generations. In 2012, Nick Hodgson summarised what was known of farmsteads to the north of Hadrian’s Wall on the Northumberland coastal plain. He concluded that a community centuries in the making suddenly collapsed at around the time the barrier became operational. Far more evidence is needed before this possibility can be assessed with confidence, but there do seem to be hints that farming communities lying south of the Wall began to follow a broadly different trajectory to those in its northern hinterland.

The Ilam Pan. It was found in 2003 and bears a flamboyant Celtic-style swirling decoration, as well as the names of four Roman forts. Here Mais – modern Bowness-on-Solway – and Coggabata – Drumburgh – can be made out. The words Vali Aeli (not visible) may disclose the Roman name for Hadrian’s Wall.

So much for the Wall’s impact on the physical world. One topic that cropped up during the 2019 Pilgrimage was the importance of integrating ancient beliefs with arguments about the Wall’s effect. A particularly thought-provoking contribution was Al McCluskey’s observation that the eventual decision to build a Roman fort on top of the seemingly important local shrine at Bewcastle could easily have played into the hands of figures advocating resistance to the Wall. It is certainly important to be mindful that the local inhabitants who had worked the region for generations and the Roman soldiers that occupied it both saw their world in very different ways to us. While Britons believed deities could dwell in important features of the landscape, such as rivers and springs, Romans would also venerate a genius loci, or protective spirit of a place. In Britain, dedications to genii loci most commonly occur in military zones, perhaps pointing to a desire to placate spirits whose tranquillity had been violated by army activity. Seen this way, the Wall potentially severed a complex ritual landscape, with – for example – mineral springs judged to hold special properties in the more recent past lying both north and south of its course. Tantalisingly, a cluster occurs in the vicinity of the Tipalt–Irthing gap.

Coventina is shown leaning on a pitcher from which water is flowing, while waving what may be a water lily.

The implications of a beautiful enamelled skillet found in 2003 and an altar discovered back in 1813 are even more intriguing. The skillet is better known as the Ilam Pan, and it is remarkable for bearing the names of four Wall forts, as well as what may have been the original Roman name for the barrier: the Vali Aeli. This can be translated as the Aelian Wall and, as Aelius was Hadrian’s family name, it would mean the original Roman name for Hadrian’s Wall was effectively also Hadrian’s Wall. As Nick Hodgson pointed out in 2017, the use of ‘Vali’ on the Ilam Pan also suggests that a dedication on the altar unearthed in 1813 to the Genio Vali – alongside the god Mars Cocidius – should be taken to mean the spirit of the Wall. If so, then at least some Roman soldiers believed that the Wall itself had a guardian spirit, which they presumably invoked because its protective powers promised to have a beneficial effect on their lives. Far from being just a physical barrier, then, the Wall also had a supernatural identity. Indeed, this combination left the monument capable of extending both physical and spiritual forms of protection.

Another striking piece of sculpture from Coventina’s sanctuary features three women who appear to be water nymphs. This may originally have stood in a shrine to the nymphs and genius loci that lies a little to the south. Both pieces are on display in Chesters Muse

More familiar names from Roman religion were also worshipped along Hadrian’s Wall. One of the finest surviving examples of sculpture from the Wall is part of a statue of Juno Regina, perched on a cow, which probably once graced the headquarters building of the Wall fort at Chesters. Other mainstream gods appearing along the Wall include Jupiter, Minerva, Mars, Mercury, Fortuna, and Hercules. But while dedications to such deities would not be out of place in the very heart of the empire, it is fair to say that the quality of carving evident on the Wall would not have won plaudits in the Eternal City. Rather than us sneering at Romano-British sculptors, though, it has been proposed that we should be mindful they were working to different expectations and traditions. Certainly, some of their most striking handiwork from the Wall depicts gods that were either local or imported by members of the army recruited from occupied provinces. Coventina, for example, was a water goddess worshipped at a cult site in the boggy valley beside Carrawburgh fort. A famous representation shows her reclining on a pitcher gushing water, while another sculpture found at the sanctuary features a triad of probable water nymphs. Coventina may have been imported from Spain or France, as possible dedications to her have also been identified there. Either way, as Lindsay Allason-Jones and Bruce McKay have pointed out, the style of her sanctuary certainly has a Continental flavour.

A statue of Juno Regina. It probably once stood in the headquarters building of Chesters fort, and now graces its wonderful site museum.

A more subtle example of this trend was found incised into the facing stone of a milecastle rampart. The image was a simple but effective rendering of a human face, which Allason-Jones noted is probably a manifestation of the Celtic obsession with heads. This fascination inspired various forms of ritual activity in northern Europe, and it is tempting to imagine that the soldier responsible for the milecastle carving had been recruited from among the Celtic heartlands, perhaps somewhere like modern France, and carried this traditional superstition into army life. While we cannot know for certain what motivated his artistry, a belief that the head could avert evil influences seems a reasonable guess.

It would be fascinating to know what the 1849 pilgrims – witnesses to established perceptions of the Wall being overturned by the discovery of the milecastle gateways – would make of talk of a Genius of the Wall, or even the notion that military activity was influenced by longstanding avenues of movement through the landscape. What is certain is that the intervening 170 years have seen generations of antiquarians, archaeologists, and Wall aficionados pursuing innovative ways to take up the gauntlet laid down by the demonstration that knowledge won from digging could reset debate. Interpretations presented to participants on the 14th Pilgrimage will themselves be refined and adjusted in the years to come, as fresh evidence opens new spheres of research or disproves current theories. If Wall scholarship and the Pilgrimage tradition endure long enough to bring as many future expeditions as past ones, then I, for one, would love to be a fly on the wall for the proceedings of the 28th Pilgrimage in 2159. By then, of course, intensive study of the monument would have been under way for longer than the operational use of the Wall during the Roman period.

An account of the pilgrimages has just been published: D. J. Breeze (2020) The Pilgrimages of Hadrian’s Wall 1849-2019: a history, Kendal: Cumberland and Westmorland Antiquarian and Archaeological Society and the Society of Antiquaries of Newcastle upon Tyne, ISBN 978-1873124840.
A 250-page review of the last decade of research on Hadrian’s Wall is available as R. Collins and M. F. A. Symonds (eds) (2019) Hadrian’s Wall: 2009-2019, Kendal: Cumberland and Westmorland Antiquarian and Archaeological Society and the Society of Antiquaries of Newcastle upon Tyne, ISBN 978-1873124826.
For the influence of the landscape on building Hadrian’s Wall, see M. F. A. Symonds (2017) Protecting the Roman Empire: fortlets, frontiers, and the quest for post-conquest security, Cambridge: Cambridge University Press, ISBN 978-1108421553.
ALL images: M Symonds, unless otherwise stated.