Antoninus became emperor in 138 A.D. For the twenty-three years that Antoninus reigned, it was remarkable for the lack of incident, because of the reports available to him of Hadrian’s glob missions, he was able to spend most of his time at the centre of government. He made a couple of adjustments to the frontier of the empire, mostly in Britain, where he built a fortified turf wall right across Clyde-Forth. It was then dismantled at about 165 A.D. He died in 161 A.D. http://www.the-romans.co.uk/good_emperors.htm