The Antonine Wall
The Emperor Antoninus Pius succeeded Hadrian in AD138 and decided to launch a new invasion of Caledonia.
Advances to both the east and west, led by the governor Lollius Urbicus, saw a series of supply forts, roads and fortlets constructed on the routes up to the new frontier line of the Forth – Clyde isthmus with Trimontium acting as a key forward base for these operations. An early event in this invasion was the siege at Burnswark, in Dumfriesshire.
Construction on the Antonine Wall and its many forts and fortlets commenced around AD142, briefly establishing a new frontier, but the wall was abandoned around AD165, four years after the death of Antoninus Pius.
The Romans fell back to Hadrian’s Wall although Trimontium continued to be occupied and remained an outpost of Rome within Caledonia until around AD180 when it seems the fort was evacuated although the reasons for this are unclear. What is known is that the native tribes were becoming more aggressive in their raids south as the Roman province of Britannia went through a period of revolt and instability.