1911 Encyclopædia Britannica/Vortigern
VORTIGERN (Guorthigirnus, Wyrtgeorn), king of the Britons at the time of the arrival of the Saxons under Hengest and Horsa. The records do not agree as to the date of the arrival of these chieftains or the motives which led them to come to Britain. It seems clear, however, that Vortigern made use of them to protect his kingdom against the Picts and Scots, and rewarded them for their services with a grant of land. Later we find the Britons at war with the new-comers, now established in Kent, and four battles are fought, in the last of which, according to the Historia Brittonum, the king's son Vortemir, their leading opponent, is slain. The Historia Brittonum is our only authority for the marriage of Vortigern with the daughter of Hengest before the war. It also records the massacre of the British nobles after the death of Vortemir and the subsequent grant of Essex and Sussex to the invaders by Vortigern.
See Historia Brittonum, ed. Th. Mommsen in Mon. Hist. Germ. xiii.; Anglo-Saxon Chronicle, ed. Earle and Plummer (Oxford, 1899); Bede, Hist. Eccl., ed. C. Plummer (Oxford, 1896).