In England, the beginning of the Viking Age is dated to 8 June 793, when Vikings destroyed the abbey on Lindisfarne, a centre of learning on an island off the northeast coast of England in Northumberland, and famous across the continent. Monks were killed in the abbey, thrown into the sea to drown, or carried away as slaves along with the church treasures, giving rise to the traditional prayer—A furore Normannorum libera nos, Domine, “From the fury of the Northmen deliver us, Lord.”

Three Viking ships had beached in Portland Bay four years earlier , but that incursion may have been a trading expedition that went wrong rather than a piratical raid. Lindisfarne was different. The Viking devastation of Northumbria’s Holy Island was reported by the Northumbrian scholar Alcuin of York, who wrote: “Never before in Britain has such a terror appeared”.