Roman Cumbria to Wallsend on the Tyne estuary, with additional military installations running down the Cumbrian coast from Bowness to Risehow, south of Maryport, in an integrated fashion (and with forts at Burrow Walls and Moresby that were perhaps not part of the system). Historians believe that the Turf Wall from the River Irthing to Bowness-on Solway was rebuilt in stone in two stages. The most easterly five miles were rebuilt at the time of Hadrian, with the remainder being rebuilt after 150 AD. However, this is open to dispute: it is uncertain whether the building works in the second half of
Legio IX Hispana 108 was the most likely explanation. Mommsen cited as evidence the Roman historian Marcus Cornelius Fronto, writing in the 160s AD, who told the emperor Marcus Aurelius: “Indeed, when your grandfather Hadrian held imperial power, what great numbers of soldiers were killed by the Jews, what great numbers by the Britons”. The emperor Hadrian (r. 117-38) visited Britain in person around 122 AD, when he launched the construction of Hadrian's Wall because, according to one Roman source, “the Britons could not be kept under Roman control”. It is plausible that Hadrian was responding to a military disaster. However, there is