The story first appears in the much later Historia Brittonum, attributed to the Welsh historian Nennius, which was a compilation in Latin of various materials (some of which were historical and others mythic, literary or legendary) put together during the early 9th century, and surviving in 9th-century manuscripts – i.e., some 400 years after the supposed events. There is no account of this event in the 6th-century writings of Gildas. The settlers, however, exploit a drunken Vortigern's lust for Hengist's daughter into allowing them to increase their numbers and granting them more land, eventually including all of the Kingdom of Kent. Legendary context Īccording to the tradition, Vortigern, who had become a high king of the Britons in the wake of the end of Roman rule in Britain, called for Anglo-Saxons under Hengist and Horsa to settle on the Isle of Thanet in exchange for their service as mercenaries in battles against the Picts and Gaels in Scotland. Most historians interpret the story as a purely literary construction. Though a popular cautionary tale in medieval Europe, there is no other historical evidence for The Treason of the Long Knives. The story is thought to be pseudohistorical as the only surviving records mentioning it are centuries later in the semi-mythological histories of the Historia Brittonum and the Historia Regum Britanniae. The Treason of the Long Knives ( Welsh: Brad y Cyllyll Hirion) is an account of a massacre of British Celtic chieftains by Anglo-Saxon soldiers at a peace conference on Salisbury Plain in the 5th century.

Historia brittonum nennius