Ambrosius Aurelianus is one of the few people that Gildas (a sixth century historian who lived in South-west Britain and wrote "De Excidio Britanniae", which focused largely on the history of Christian Britain) identifies by name in his sermon "De Excidio et Conquestu Britanniae", and the only one named from the 5th century. Following the destructive assault of the Saxons, the survivors gather together under the leadership of Ambrosius, who is described as: