The emperor Hadrian visited Britannia in AD 122 and ordered his generals to build a wall from the Tyne to the Solway, to prevent raiders from the north destroying the strategic Roman base at Corbridge, in Northumberland.
Hadrian’s Wall was 80 Roman miles long - about 73 modern miles or 117 km. It was built in 5 mile stretches, with seventeen forts. Smaller forts called ‘milecastles’ were built every mile and between these were signal turrets.
Building the wall was a huge undertaking; it took 15 years to build, and sons followed fathers into guarding the wall. Eighteen thousand soldiers worked on it, and 4 million tonnes of stone were used. It served as a frontier for several Roman incursions into Caledonia.
Much of Hadrian's Wall was about 10 Roman feet wide - 3m or 9.7 modern feet. It stood about 5 to 6 metres tall (16 to 20 feet). It was about a third wider at the base than it was at the ramparts.
By AD 367 the wall was attacked by an alliance of tribes as part of the‘Barbarian Conspiracy’. The Roman peace – ‘Pax Romana’ - was restored for a short time, but by AD 400 the Empire which had stretched from Newcastle to the Nile was in crisis and the frontier was abandoned.
