History of Hadrian’s Wall
Hadrian’s Wall was the north-west frontier of the Roman empire for nearly 300 years. It was built by the Roman army on the orders of the emperor Hadrian following his visit to Britain in AD 122. At 73 miles (80 Roman miles) long, it crossed northern Britain from Wallsend on the River Tyne in the east to Bowness-on-Solway in the west. The most famous of all the frontiers of the Roman empire, Hadrian’s Wall was made a World Heritage Site in 1987.
When was Hadrian’s Wall built?
Permanent conquest of Britain began in AD 43. By about AD 100 the northernmost army units in Britain lay along the Tyne–Solway isthmus. The forts here were linked by a road, now known as the Stanegate, between Corbridge and Carlisle.
Hadrian came to Britain in AD 122 and, according to a biography written 200 years later, ‘put many things to right and was the first to build a wall 80 miles long from sea to sea to separate the barbarians from the Romans’.
The building of Hadrian’s Wall probably began that year, and took at least six years to complete. The original plan was for a wall of stone or turf, with a guarded gate every mile and two observation towers in between, and fronted by a wide, deep ditch. Before work was completed, 14 forts were added, followed by an earthwork known as the Vallum to the south.
The inscription on the Ilam pan, a 2nd-century souvenir of Hadrian’s Wall found in 2003, suggests that it was called the vallum Aelii, Aelius being Hadrian’s family name.
A change of plan
Before the first plan was completed, a radical change led to the placing of forts on the wall line and down the Cumbrian coast, and the construction of an earthwork to the south.
The forts, each apparently built for a single unit and at a basic spacing of 7⅓ miles, were placed astride the Wall wherever possible. This allowed three main gates, each with two entrances, making the equivalent of six milecastle gates, to provide access to the north; the double-portal south gate was supplemented by two small side gates. The position of the forts and the provision of so many gates suggest that a requirement for increased mobility led to this change.
The addition of the forts was followed by the construction of an earthwork to the south 120 Roman feet (an actus – about 35 metres) wide. This consisted of a central ditch between two mounds. Causeways, surmounted by gates, were provided at forts. The purpose of the Vallum, as this earthwork is known, was presumably to protect the rear of the frontier zone.
After the forts had been added, the width of the Wall was narrowed to 8 Roman feet (2.4 metres) or less and the standard of craftsmanship reduced, both presumably in order to speed work.
Who manned the wall?
Although mainly built by legionaries, the Wall was manned by auxiliaries. They were organised into regiments nominally either 500 or 1,000 strong and either infantry or cavalry or both. The 500-strong mixed infantry and cavalry unit was the workhorse of the frontier. Each fort on the Wall appears to have been built to hold a single auxiliary unit.
The troops based in the forts and milecastles of the Wall were mostly recruited from the north-western provinces of the Roman empire, though some were from further afield.
Army units tend to be accompanied by camp followers. Little is known about these people in the early years of the Wall; it would appear that they were not allowed to settle in the zone between the Wall and the Vallum. Excavation has demonstrated the existence of civil settlements in the 3rd century and geophysical survey has recorded the urban sprawl spreading well beyond the forts. These remains are, however, undated.
After the Romans
With the abandonment of Britain by the central authorities, it is less clear what happened. At Birdoswald, a case had been made for life at the fort continuing, with the regimental commander perhaps turning into a local chieftain.
In the years that followed, Hadrian’s Wall became a quarry for the stone to build castles and churches, farms and houses along its line, until the conservation movement in the 18th and 19th centuries put a stop to that. It was only from the mid-19th century onwards that early archaeologists and historians such as John Clayton, John Hodgson and John Collingwood Bruce began to study Hadrian’s Wall in earnest and sought to protect its still magnificent remains. To read more about this see Research on Hadrian’s Wall.
About the Author
David Breeze is former Chief Inspector of Ancient Monuments for Scotland and Visiting Professor of Archaeology at the University of Durham. He is the author of the English Heritage guidebook to Hadrian’s Wall and co-author of Hadrian’s Wall, the standard work on the Wall.