The Interregnum of Severus was a legendary time in British history following the death of St. Lucius as accounted by Geoffrey of Monmouth. When Lucius died, the Britons began to rebel against the power of Rome. In response, the Senate requested Emperor Severus to quell the rebellion on the island. He landed with two legions of soldiers and began to fight the Britons. He continued to fight them up to the border between Deira and Albany, modern day Scotland. The northern Britons united under the leadership of Sulgenius who attacked both Romans and Briton allies of Rome. Unable to defeat Sulgenius, Severus built a enormous rampart on the border which today is known as Antonine Wall.

Sulgenius fled Britain and gathered together a large army of Picts from Scythia. He returned and attacked York in February, 211. Most of the tribes of Britain joined Sulgenius and Severus was forced to retaliate. He attacked York with all the Romans and the remaining loyal British tribes. It was there that he died and Sulgenius was mortally wounded. Severus was buried in York after his legions regained control of it. The Roman legions elected Severus's son Geta to the kingship of Britain.