Gildas, Saint (gil'dus) [key], d. 570, British historian, possibly a Welsh monk. Shortly before 547 he wrote the De excidio et conquestu Britanniae, a Latin history of Britain dealing with the Roman invasion and the Anglo-Saxon conquest of England, the earliest authority for the period. Gildas is said to have gone to Brittany and to have founded the monastery named after him near Vannes. He explained the Germanic invasions as God's punishment for the sins of the Romano-British Christians.
