Completed in 1136, "The History of the Kings of Britain" traces the story of the realm from its supposed foundation by Brutus to the coming of the Saxons some two thousand years later. Vividly portraying legendary and semi-legendary figures such as Lear, Cymbeline, Merlin the magician and the most famous of all British heroes, King Arthur, it is as much myth as it is history and its veracity was questioned by other medieval writers. But Geoffrey of Monmouth's powerful evocation of illustrious men and deeds captured the imagination of subsequent generations, and his influence can be traced through the works of Malory, Shakespeare, Dryden and Tennyson.

Geoffrey of Monmouth (c.1100 – c.1155) was a clergyman and one of the major figures in the development of British history and the popularity of tales of King Arthur.

Geoffrey of Monmouth's Historia Regum Britanniae (English: The History of the Kings of Britain) is a pseudohistorical account of British history, written around 1136. It chronicles the lives of the kings of the Britons in a chronological narrative spanning a time of two thousand years, beginning with the Trojans of Homer's Iliad founding the British nation and continuing until the Anglo-Saxons assumed control of Britain around the 7th century. It is one of the central pieces of the Matter of Britain.

(Wikipedia)