When was Hadrian’s wall built? About the same time?
The siting and route of Hadrian’s Wall was largely determined by the natural landscape. There’s evidence of a wooden palisade and turf barrier that antedates the wall. It was begun under Hadrian (sez here 122 AD). 45 or so years earlier Agricola had built temporary forts in what is now Scotland, and had apparently intended to conquer the whole of the British Isles, but it’s likely that the expense of the campaign exceeded the value of the lands and everything and everyone there. Twenty years after Hadrian’s Wall, the Antonine Wall was built on the order of Antoninus Pius, begun 142 AD. The Romans withdrew to Hadrian’s Wall about 162 AD.
It’s likely that the Caledonian population in the area between the walls either requested help from raids by their none-too-neighborly neighbors to the north, or the Romans saw an opportunity to add a friendly population to the Empire without a lot of trouble. Contrary to the claymore-swingers, there was no Scottish population in Caledonia, and the Romans didn’t build Hadrian’s Wall out of terror of barbarian attacks.
https://freerepublic.com/tag/hadrianswall/index
https://freerepublic.com/tag/antoninewall/index
https://en.wikipedia.org/wiki/Hadrian%27s_Wall#Purpose_of_construction
https://en.wikipedia.org/wiki/Gnaeus_Julius_Agricola
https://freerepublic.com/focus/chat/4195145/posts?page=14#14