Hadrian's Wall (AD 122): Rome's Frontier in Northern Britain

Hadrian’s Wall is a Roman frontier wall in northern England, begun in AD 122 on the orders of the emperor Hadrian. It ran for 80 Roman miles (about 117 km) from Wallsend on the River Tyne to Bowness-on-Solway, with forts, milecastles, turrets and a great earthwork behind it. For most of the following three centuries it marked the northern edge of Roman Britain, and today it is the best-known monument of the Roman Empire in Britain and part of a UNESCO World Heritage Site.

Background: Rome in northern Britain

The Romans invaded Britain in AD 43 (see Roman conquest of Britain) and gradually pushed north. Under the governor Agricola, Roman armies campaigned deep into Scotland and won the Battle of Mons Graupius in AD 83 or 84. But troops were soon withdrawn for wars on the Danube, and the far north was given up.

By around AD 105 the frontier had settled on the Tyne-Solway isthmus, the narrowest neck of land in northern England. A road known today as the Stanegate linked forts such as Corbridge, Vindolanda and Carlisle. The Vindolanda tablets, written by soldiers and officials there around AD 90-120, give a vivid picture of this earlier frontier. There are hints in the sources of serious trouble in Britain early in Hadrian’s reign.

Hadrian’s decision

Hadrian, who became emperor in AD 117, abandoned expansion in favour of consolidating the empire’s borders. In Germany he built a timber palisade along the frontier. In AD 122 he visited Britain in person, and the building of the wall is closely linked to that visit.

The Historia Augusta, a late Roman collection of imperial biographies, states that Hadrian was the first to build a wall, 80 miles long, to separate the Romans from the barbarians. Building inscriptions name the governor Aulus Platorius Nepos, who arrived in Britain in 122, as responsible for the work.

Building the wall

The wall was built by legionaries from the three legions stationed in Britain: the Second Augusta, the Sixth Victrix and the Twentieth Valeria Victrix. Inscriptions set up by individual work gangs record which section each built.

The eastern part, from Newcastle to the River Irthing, was built of stone, at first about 10 Roman feet (3 m) wide. Before it was finished, the width was reduced to about 8 feet or less, and archaeologists can still see where “broad wall” foundations carry a narrower wall. The western 31 Roman miles, from the Irthing to the Solway, were first built of turf and timber, probably because suitable stone and lime were scarce; this section was rebuilt in stone later in the 2nd century. The wall’s original height is unknown; estimates usually suggest around 4-5 metres including any parapet.

The design was highly regular. A small fortlet called a milecastle, with a gate through the wall, stood every Roman mile, and two stone turrets stood between each pair of milecastles. In front of the wall to the north ran a deep ditch, except where cliffs made it unnecessary, as along the dramatic crags of the Whin Sill in Northumberland.

Forts and the Vallum. The original plan seems to have kept the main garrison in the Stanegate forts behind the line. During construction this changed. Around 14-16 full-size forts were added on the wall itself, among them Segedunum (Wallsend), Chesters, Housesteads and Birdoswald. The wall was also extended east from Newcastle to Wallsend.

At about the same time, a great earthwork called the Vallum was dug south of the wall: a flat-bottomed ditch flanked by mounds, running almost the whole length. It defined a military zone and controlled access from the south, with crossings only at the forts. Together, the ditch, wall and Vallum formed a broad controlled strip across the island.

What the Romans called it. No ancient text uses the name Hadrian’s Wall. Two small enamelled bronze vessels, apparently souvenirs, list forts on the western part of the line: the Rudge Cup, found in Wiltshire in 1725, and the Staffordshire Moorlands Pan, found by metal detectorists in 2003. The pan also bears the words “rigore vali Aeli”, which many scholars read as “on the line of the Aelian wall”. If so, the Romans may have called it the Vallum Aelium, after Hadrian’s family name, Aelius.

How the frontier worked

The wall was not a fighting platform like a medieval castle. Roman armies preferred to fight in the open, and the wall’s garrison was too thinly spread to hold every point against a determined attack. Instead, it worked as a controlled barrier. Gates at the milecastles and forts allowed people and goods to cross under supervision, where they could be inspected and taxed. Lookouts in turrets could signal trouble, and the forts housed units able to pursue raiders.

The garrison consisted of auxiliary regiments, non-citizen soldiers from across the empire. Inscriptions show units originally raised in what are now Belgium, the Netherlands, Germany, Spain, Romania and Syria, among others. Estimates of the total number of troops on the wall vary, typically from about 9,000 to 15,000 at its height, including outpost forts north of the line.

Civilian settlements, called vici, grew up outside many forts. Traders, craftsmen, soldiers’ families and others lived there. Altars, tombstones and finds such as shoes, letters and jewellery show a mixed frontier society, including people from North Africa and the Near East.

The Antonine Wall and later changes

Hadrian died in 138. His successor, Antoninus Pius, advanced north and from about AD 142 built a new turf barrier, the Antonine Wall, between the Forth and the Clyde in Scotland. Hadrian’s Wall was partly decommissioned. By the 160s the Romans had withdrawn from the Antonine Wall, and Hadrian’s Wall became the frontier again.

The emperor Septimius Severus campaigned in Scotland in AD 208-211 and carried out major repairs to Hadrian’s Wall, so thorough that early modern antiquarians long thought he had built it. Severus died at York in 211. In the 3rd and 4th centuries the forts changed: garrisons shrank, barracks were rebuilt as rows of small houses and some forts may have housed soldiers’ families inside the walls. Occupation continued until the end of Roman rule in Britain in the early 5th century, after which the garrisons slowly faded away.

Later history and rediscovery

Life did not end abruptly when Roman rule did. At Birdoswald, archaeologists found timber halls built over the granaries in the 5th century, suggesting a local leader kept a community there. In the early 8th century the Northumbrian monk Bede described the wall, still standing to an impressive height near his monastery at Jarrow, although he attributed parts of it to the wrong emperors.

For centuries after Rome left, the wall was a convenient quarry. Its dressed stones were reused in churches, farms and castles across the region. In the 1750s, after the Jacobite rising of 1745, General Wade’s Military Road between Newcastle and Carlisle was built over long stretches of the wall, destroying them.

Antiquarians began recording the wall in the 16th to 18th centuries. In the 19th century the Newcastle lawyer John Clayton bought large stretches of the central sector, including Housesteads and Chesters, and protected and excavated them. His work is the main reason the wall survives so well in Northumberland.

Hadrian’s Wall became a UNESCO World Heritage Site in 1987, and in 2005 it became part of the transnational “Frontiers of the Roman Empire” site together with the Upper German-Raetian Limes, joined by the Antonine Wall in 2008. The Hadrian’s Wall Path National Trail opened in 2003.

Myths and facts

Myth: The wall marks the border between England and Scotland. It lies wholly in England; the modern border is further north and was set in the Middle Ages.

Myth: It was built to keep out the Scots. The Scots, in the sense of the people from Ireland who gave Scotland its name, arrived later. In Hadrian’s time the peoples north of the wall included the Caledonians, Votadini and Selgovae, and later the Picts.

Myth: Roman soldiers on the wall were all Italians. The garrison was mostly auxiliaries recruited from the provinces, and by the 3rd century many were born locally in Britain.

By the numbers

Timeline

• AD 43: Roman invasion of Britain.
• c. AD 105: Frontier settles on the Stanegate road between Tyne and Solway.
• AD 122: Hadrian visits Britain; construction of the wall begins under Aulus Platorius Nepos.
• c. AD 128: Main structure largely complete, with forts and Vallum added.
• c. AD 142: Antoninus Pius begins the Antonine Wall further north.
• c. AD 160s: Hadrian’s Wall restored as the frontier.
• AD 208-211: Septimius Severus campaigns in Scotland and repairs the wall.
• c. AD 400-410: Roman rule in Britain ends; garrisons decline.
• 1987: Hadrian’s Wall becomes a UNESCO World Heritage Site.

Why it matters

Hadrian’s Wall is the most complete surviving land frontier of the Roman Empire. It shows how Rome defined and controlled its borders, how a multinational army lived far from home, and how a frontier shaped the landscape and identity of northern Britain for centuries. Hadrian’s taste for building on a vast scale can also be seen at Hadrian’s Villa at Tivoli.