THE ANTONINE WALL, built in the second century on the orders of the Emperor Antoninus Pius, stretched from the Forth to the Clyde in Scotland. Much of the construction was turf. The defensive capacity was therefore different from a wall like Hadrian’s. Still, it must have been at the least an interruption for locals to encounter the Antonine life in full swing, even when or if there were no active hostilities. Oiled Romans might have been scraping themselves with strigils. Others might have been gambling; yet others soaking, chilling or steaming under the eyes of a curvaceous stone Fortuna. What would the person surprised by them – herder, laundress, domestic traveller following one of those lightly landmarked, muscle-remembered paths which do not require built lines and look like nothing to people who do not walk them, so do not know them – have noticed first? The interruption of the view? The light winking from the mica in sandstone? The noise?

The babble would have been a not entirely Latinate Babel. The Romans who worked at the Wall were a varied lot; archers, horsemen, consumers who were an attractive market for skilled workers and foreign traders; connected to Thuringia, Scythia, Arabia. They left behind a great many North African cooking vessels. In the Hunterian Museum, you can see a seal of the kind likely to have been used by a high-ranking man on his letters home; where was that home? Where were these ‘Romans’ from? How much of the Romano-Celtic design on stone and other items indicated forced labour, how much ...