Vortigern (/ˈvɔːrtɪdʒɜːrn/;Old Welsh Guorthigirn, Guorthegern; Welsh: Gwrtheyrn; Old English: Wyrtgeorn; Old Breton Gurdiern, Gurthiern; Irish: Foirtchern; Latin: Vortigernus, Vertigernus, Uuertigernus, etc), also spelled Vortiger, Vortigan, and Vortigen, was possibly a 5th-century warlord in Britain, known perhaps as a king of the Britons, at least connoted as such in the writings of Bede. His existence is nonetheless contested by scholars, and information about him is obscure.
He may have been the "superbus tyrannus" said to have invited Hengist and Horsa to aid him in fighting the Picts and the Scots. However, they revolted, killing his son in the process and forming the Kingdom of Kent. It is said that he took refuge in North Wales, and that his grave was in Dyfed or the Llŷn Peninsula. The historian Gildas denigrated Vortigern for his misjudgement and also blamed him for the loss of Britain. He is cited at the beginning of the genealogy of the early Kings of Powys.