Gildas, a sixth-century British monk, is known as the author of De Excidio Britonum [The Ruin of Britain], an impassioned account in highly-wrought Latin of the downfall of his country-people and of their conquest by the pagan Anglo-Saxons, due to their sinfulness and the failings of their secular and ecclesiastical leaders. He calls upon the people to repent before they are completely swept away. The work is a key source for fifth-century Britain, though it is characterized by denunciatory fervour rather than attention to specific historical detail. Gildas wrote the De Excidio around the year 540, when, as he tells us, he was forty-three years old.
The few other reliable facts about his life are based on …
Magennis, Hugh. "Gildas". The Literary Encyclopedia. First published 20 September 2002
[http://www.litencyc.com/php/speople.php?rec=true&UID=1743, accessed 29 March 2017.]