The Wall of Severus was possibly a defensive fortification built by the Roman Emperor Septimius Severus (reigned AD 193–211) in Britannia during the emperor's campaign there. Three texts mention the wall:
Tradition interprets these and other early sources as referring either to the Antonine Wall or to Hadrian's Wall. However, if Severus did build a wall, it has been speculated that it may be the origin of Offa's Dyke, which has been dated back to at least the mid-5th century, thus predating the reign of Offa of Mercia in the 8th century.