The name usually given to the remains of the Roman fortifications which defended the northern frontier of the Roman province of Britain, between the Tyne and the Solway. The works consisted of (I) a continuous defensive rampart with a ditch in front and a road behind; (2) various forts, blockhouses and towers along the rampart; and (3) an earthwork to the south of it, generally called the Valium, of uncertain use. The defensive wall was probably first erected by Hadrian about A.D. 122 as a turf wall, and rebuilt in stone by Septimius Severus about A.D. 208. See further BRITAIN: Roman.