After Hadrian’s death in A.D. 138, his successor Antoninus Pius (reign A.D. 138-161) adopted a radically different policy in Britain. He abandoned Hadrian’s Wall and made a concerted effort to conquer the Scottish lowlands. After having some success, he built a new line of fortifications in Scotland known as Antonine’s Wall.
Antoninus’ conquest proved only temporary and by the end of his reign, the Scottish fortifications had been abandoned and Hadrian’s Wall reoccupied.
A series of modifications were then made to the wall, including the replacement of the turf portion in favor of stone and the construction of a road called the “military way” to the south of the wall. In addition, Collins notes, the turrets appear to have been decommissioned and the gateways of the milecastles narrowed.
As time went on more changes occurred. In the fourth century, as the Roman Empire came under greater military pressure, Collins notes that the gates of the milecastles were narrowed further and some blocked off altogether.
After the collapse of the Roman Empire in the fifth century, and the beginning of the Dark Ages, the political landscape of Britain changed and the wall became “politically redundant,” Collins writes. Its fortifications were quarried for stone, some of them being used to help build England’s medieval castles, the country’s new premier fortifications.
