The story of the Britons. Merlin"s life

Galfrid of Monmutsky presented the "History of the Britons" as the true story of Britain from the settlement of her Brutus, a descendant of the Trojan hero Aeneas, to the death of Cadvalalad in the 7th century. In particular, this work contains stories about the invasion of Caesar, Leira and Kimbeline (retold by Shakespeare in the "King Lyra" and "Tsimbeline"), and King Arthur.
Galfried claims that their source was a very ancient book in the British language ", which Walter Oxford allegedly handed him, but in the very existence of this book, most scientists doubt it. The History ... "almost does not contain historical information, and already in 1190 William Newburgsky wrote: “It is completely clear that everything written by this person about Arthur and his heirs, and his predecessors from the warrior, were partially invented by himself, Partly others - either from indefatigable love for lies, or to amuse Britons. "