Scotland during the Roman Empire soon after 160. The destruction of some of the southern brochs may date to the Antonine advance, the hypothesis being that whether or not they had previously been symbols of Roman patronage they had now outlived their usefulness from a Roman point of view. The Roman frontier became Hadrian's Wall again, although Roman incursions into Scotland continued. Initially outpost forts were occupied in the south-west and Trimontium remained in use but they too were abandoned after the mid-180s. Roman troops, however, penetrated far into the north of modern Scotland several more times. Indeed, there is a greater density of Roman
Scotland during the Roman Empire fortification built across the width of what is now northern England. The wall was 80 Roman miles (73.5 statute miles or 117 kilometres) long, its width and height dependent on the construction materials which were available nearby. East of the River Irthing the wall was made from squared stone and measured 3 metres (9.7 ft) wide and 5–6 metres (16–20 ft) high, while west of the river the wall was originally made from turf and measured 6 metres (20 ft) wide and 3.5 metres (11.5 ft) high; it was subsequently rebuilt in stone. The wall was augmented by various ditches,