Little is definitively known of the life and schooling of Geoffrey of Monmouth, but his extraordinary literary works have survived centuries as a testament to his legacy. Around the time of Geoffrey's life, the written Arthurian legends were mostly fragmentary and often incoherent. He therefore took on the task of creating the first full biographies of King Arthur and Merlin, which from that point on remained the quintessential source for all Arthurian legend tales. His finest work, "The History of the Kings of Britain", traces the reign of nearly a hundred British kings, beginning with the nation's mythical founder, Brutus. It is an imaginative and meticulously written masterpiece. Modeled after the Ænied, one half of the work is devoted towards the first ten centuries of British history. The second half, comprising about two centuries, focuses primarily around King Arthur, the rise and fall of the Round Table, and the declining fortunes of Arthur's heirs.