Running for 73 modern or 80 Roman miles from Wallsend on the River Tyne to Bowness on the Solway Firth, Hadrian’s Wall is the best known visible remains of a Roman frontier today. Consisting of an almost unbroken line of stone wall, punctuated by mile castles and forts, it protected Rome’s northern territories from the first century AD until the end of Roman Britain.
The History of Hadrian’s Wall
Hadrian’s Wall was built in the early second century AD to protect Rome’s British territories. Despite defeating the Caledonians at the Battle of Mons Graupius forty years after the conquest of southern Britain, the Romans were forced to withdraw their lines south to the estuaries of the River Tyne and the Solway Firth. An unofficial frontier was established between these two points, with a road running between Carlisle and Corbridge for communications.
No formal defences existed until the 120s AD when the Emperor Hadrian set the extent of the Roman empire to stabilise it and allow for the effective defence of existing Roman territory. So a wall was ordered to be built across the neck of what is now Northern England.
The wall took six years to build, using the labour of Roman army units from Caerleon, York and Chester. Roman legions were routinely staffed with skilled engineers, architects, surveyors, and masons with the requisite construction work skills.
Initially, a small sector of the wall was constructed of turf embankments, but eventually, this was replaced until the entire length of the wall was built from stone. Various other upgrades and modifications took place over time.
After Hadrian’s death, his wall was abandoned for twenty years in favour of the Antonine Wall, built 100 miles north between the Forth and Clyde estuaries in response to Roman advances made under the Emperor Antoninus Pius. However, this wall was quickly abandoned and Hadrian’s Wall was reoccupied, only falling into gradual disuse in the fifth century AD after the Roman withdrawal from Britain.
Fortifications of Hadrian’s Wall
Soldiers did not patrol the length of the wall or attempt to use it to defend Roman territory. Instead, the wall acted as a barrier, just one part of a series of defensive fortifications designed to control military and civilian movements across the frontier.
A series of ditches and embankments lay on either side of the wall for its entire length. To the north, a 10ft deep, 30ft wide ditch was constructed in areas without natural defensive features such as crags and escarpments. This northern side was slightly higher, putting anyone attempting to approach the wall from the ditch at a disadvantage by making them more visible and exposed.
Behind the wall and the Roman road in Roman territory ran the wall’s vallum, a 10-foot deep, 20 ft wide ditch flanked by two 10ft high and 20ft wide mounds. This effectively functioned as the border of the empire. It was only possible to cross the vallum at Roman forts that housed troops ready to be deployed into enemy territory. But there were plenty of opportunities to cross Hadrian’s Wall because forts along the Wall were prolific.
While forts controlled crossings of the vallum, mile castles controlled crossings over the wall into non-Roman territory. As the name “milecastle” suggests, these structures were found a mile apart along the wall’s length. Each mile castle consisted of two turrets flanking an access gateway. Each mile castle had barracks to house the troops that manned it. Generally, only eight men were required at one time in a mile castle, although one example was built to take thirty-two men.
Resources
Breeze, David, Hadrian’s Wall: A Souvenir Guide to the Roman Wall. English Heritage
