The Britain of 1,800 years ago was a much different place to now, with no clear distinction between the now Wales, Scotland and England but a collection of regions run by indigenous tribes under Roman occupation.
There were areas that even the Roman army feared to tread during this time such as the north of Scotland where two great walls were built to keep the troublesome locals out, namely the walls of Emperors Hadrian and Antonius.
There was a third great wall constructed during the Roman occupation however, the location of which has seen great debate amongst scholars over the years and that is the wall of the Emperor Septimus Severus.
Current thinking leans towards this wall being a restoration of Hadrian's earlier construction but even the records kept by the Romans themselves points to this