Roman frontier barrier in Britain.
It ran 37 mi (59 km) across Scotland between the River Clyde and the Firth of Forth. Ordered by Antoninus Pius and built in AD 142 by the governor of Britain, it was about 15 ft (5 m) wide and 10 ft (3 m) high; a ditch 40 ft (12 m) wide and 12 ft (4 m) deep ran in front of it and a road behind. It was controlled by 19 forts spaced at intervals of 2 mi (3 km). Its construction moved the northern boundary of Roman Britain into Scotland, providing defense against the northern tribes beyond Hadrian's Wall , which lay to the south. The wall was abandoned by 196, but traces remain.