Gildas

Gildas (c. 500 – 570) was a 6th-century British cleric. He is one of the best-documented figures of the Christian church in the British Isles during this period. His renowned learning and literary style earned him the designation Gildas Sapiens (Gildas the Wise). His work De Excidio et Conquestu Britanniae, which contains narratives of the post-Roman history of Britain, is the only substantial source for history of this period written by a near-contemporary. He was ordained in the Church and, in his works, favours the monastic ideal. Fragments of letters he wrote reveal that he composed a Rule for monastic life that was somewhat less austere than the Rule written by his contemporary, Saint David, and set suitable penances for its breach.

Read more about Gildas:  Life, De Excidio Et Conquestu Britanniae