answers: Historia Regum Britanniae
context: was "The History of the Kings of Britain", the work best known to modern readers. It relates the purported history of Britain, from its first settlement by Brutus of Troy, a descendant of Trojan hero Aeneas, to the death of Cadwaladr in the 7th century, covering Julius Caesar's invasions of Britain, Kings Leir and Cymbeline, and one of the earliest developed narratives of King Arthur. Geoffrey claims in his dedication that the book is a translation of an "ancient book in the British language that told in orderly fashion the deeds of all the kings of Britain", given to him </s> has] come across in many years because it so deeply engages questions that matter." The New York City-based theater troupe Guerilla Shakespeare Project produced a stage version of "The Tragedy of Arthur" in 2013 with Phillips' involvement. It opened to mixed reviews. The Tragedy of Arthur The Tragedy of Arthur is a 2011 novel by the American author Arthur Phillips. The narrative concerns the publication of a recently discovered Arthurian play attributed to William Shakespeare, which the main narrator, "Arthur Phillips", believes to be a forgery produced by his father. It was published by Random House. The book takes the </s> up the Matter of Britain. The legendary Arthur developed as a figure of international interest largely through the popularity of Geoffrey of Monmouth's fanciful and imaginative 12th-century "Historia Regum Britanniae" ("History of the Kings of Britain"). In some Welsh and Breton tales and poems that date from before this work, Arthur appears either as a great warrior defending Britain from human and supernatural enemies or as a magical figure of folklore, sometimes associated with the Welsh otherworld Annwn. How much of Geoffrey's "Historia" (completed in 1138) was adapted from such earlier sources, rather than invented by Geoffrey himself, is unknown.
question: who wrote the first book about king arthur