Hadrian's Wall

Hadrian's Wall is a Roman frontier barrier that crossed the whole width of northern England, running westward from Wallsend on the River Tyne to Bowness-on-Solway on the Solway Firth. Begun in 122 CE under the emperor Hadrian, it ran for 80 Roman miles, about 117 kilometres, with forts, small milecastles and turrets along its length and great ditches in front of and behind it. It marked the north-western edge of the Roman Empire for most of the following three centuries and is the largest Roman archaeological monument in Britain. Despite a common belief, it lies wholly in England and has never formed the border with Scotland.

Hadrian gave up his predecessor Trajan's policy of conquest in favour of holding existing frontiers, and in Britain, unlike on the Rhine or Danube, there was no great river to serve as a boundary. There was unrest in the province when he came to the throne in 117, and the wall was probably planned before his visit to Britain in 122. Its main purpose seems to have been to slow raiders and to channel movement through gates, where people could be watched and taxed, rather than to serve as a continuously manned fighting line. It was also a statement of Roman power; there is some evidence that it was plastered and whitewashed. The archaeologist Neil Faulkner called it "as much a propaganda statement as a functional facility". Some historians, including David Breeze and B. Dobson, have suggested that Hadrian may have heard of the Great Wall of China, while others, such as Duncan B. Campbell, argue that Mediterranean wall-building traditions are explanation enough.

Soldiers of three legions, the Second Augusta, the Sixth Victrix and the Twentieth Valeria Victrix, built most of the wall in about six years. Plans changed during the work: the stone wall was narrowed from ten Roman feet to eight, and the western part, from Milecastle 49 onwards, was first built in turf and later rebuilt in stone. South of the wall ran the Vallum, a broad ditch between two mounds, whose relationship to the wall has long been debated. When fully manned the frontier probably held almost 10,000 soldiers, mostly auxiliary infantry and cavalry recruited from across the provinces rather than the legionaries who built it.

The wall cut through a region of farming settlements that had shared a common culture since about 200 BCE. Roman-style settlement quickly appeared to the south, while to the north the building tradition of large roundhouses faded, and Roman coins and pottery rarely crossed the line.

After Hadrian died in 138, Antoninus Pius pushed the frontier north to a new turf barrier, the Antonine Wall, in what is now central Scotland. It was soon given up, and under Marcus Aurelius Hadrian's Wall became the main frontier again in 164. Septimius Severus campaigned in Caledonia between 208 and 211 without lasting result. In the late fourth century invasions and internal troubles weakened Roman control, and by about 410 the Roman army and administration had left Britain. Some forts stayed occupied into the fifth century, perhaps by local Britons.

The abandoned wall became a quarry. Its stone went into local buildings, including the church at Jarrow dedicated in 685, where the scholar Bede lived; Bede described it as eight feet wide and twelve high. In the eighteenth century long stretches were demolished to build General Wade's military road after the Jacobite rising of 1745. The antiquarian John Clayton, town clerk of Newcastle, began buying land along the central section in 1834 to stop farmers removing stone, excavated forts such as Housesteads and Chesters, and restored sections of the wall. Much of this land later passed to the National Trust.

UNESCO declared Hadrian's Wall a World Heritage Site in 1987, and since 2005 it has been included in the transnational Frontiers of the Roman Empire site; the Antonine Wall was added in 2008. Although none of it stands to its full height, many of its forts have been excavated and are open to the public, and a footpath follows its line across the United Kingdom's northern counties. New finds still occur, such as a three-metre stretch uncovered beneath a Newcastle street in 2021.