By the AD180s the Romans controlled much of what is now Scotland but had to transfer troops to deal with problems on the Danube. The army fell back to the isthmus between the Tyne and the Solway and constructed a line of forts along a military road - the Stanegate.
Hadrian’s decision to build the Wall just north of the Stanegate road was part of his policy to consolidate the Empire’s frontiers after he became Emperor in AD117. Evidence suggests he inspected work on the Wall in person in AD122.
The Wall extended across the narrowest part of the country, from Bowness-on-Solway in the west to Wallsend in the east, a distance of 80 Roman miles or 73 modern miles (117 km). From the river Irthing to Bowness the Wall was initially constructed of turf, and along with a line of defences down the Cumbrian coast, may have been the first part of the frontier to be built in response to threats from native tribes in this area.
The military structures along Hadrian’s Wall were highly organised. Major forts were located 8.2 Roman miles (11.5 km) apart. Between these were smaller fortlets (milecastles) one Roman mile apart, with two small turrets or lookout stations between every milecastle. Communications were relayed using beacons and semaphore signals.
There’s a scale model of the whole length of Hadrian’s Wall at The Hadrian’s Wall Gallery in the Great North Museum (also known as The Hancock), alongside sculpted stones and other objects collated from many different sites.