Geoffrey was the first writer to compile the ancient legends of King Arthur and his knights of the Round Table. They are contained in his principal work History of the Kings of Britain. The work was written in Latin, probably between 1130 and 1138. It recounts the lives of British kings from Brutus, the legendary great-grandson of Aeneas, to Cadwaladr, who died in 689 A. D.
In writing his works, Geoffrey relied not only on earlier Latin histories and oral tradition, but also on his own imagination. Although his inadequacy as a historian has been proved, his work was widely accepted as fact until the 17th century. It was also the source for many poems, romances, and historical plays. Another work attributed to him is a Latin poem, The Life of Merlin. Geoffrey became a priest in later life, and he was made Bishop of St. Asaph in Wales in 1152.
