Geoffrey of Monmouth wrote his History of the Kings of Britain back in the 12th century. It was at the behest of Robert of Gloucester, his patron, that he claims to have transcribed/copied/invented his history, placing King Arthur at the center of a national–and by that I mean English–origin myth. The idea was to justify the conquest of Britain by the Normans as a mirror to what King Arthur had done in the 5th century, including crossing the English Channel from Normandy to Britain.
Children’s author Phillip Womack (author of The Other Book and The Liberators) said in the Times Online: “As inhabitants of these islands, we don’t have many myths that bring us together, but King Arthur is one. I think that we will always seek him as a saviour, whatever situation we’re in, because that’s human nature. The reason the Arthur myths are currently so popular is that they reflect our age brilliantly.”
This is a nice quote, and not at all inaccurate, but none-the-less astonishing because this is EXACTLY WHAT GEOFFREY OF MONMOUTH INTENDED! He wrote his book in 1139 AD. It was meant to be a mythology for the nation of England, justifying the Norman conquest of England (and particularly Empress Maud’s claim to the throne) and placing her in the line of rulers dating back to King Arthur and earlier.
Geoffrey’s book was an immediate hit, and for the most part taken by the populace to be ‘true’, even if the scholars at the time dismissed it. One site states: “There is nothing in the matter or the style of the Historia to preclude us from supposing that Geoffrey drew partly upon confused traditions, partly on his own powers of invention, and to a very slight degree upon the accepted authorities for early British history. His chronology is fantastic and incredible; William of Newburgh justly remarks that, if we accepted the events which Geoffrey relates, we should have to suppose that they had happened in another world.”
Furthermore: “William of Newburgh . . . belongs to the northern school of historians, who carried on the admirable traditions of the Venerable Bede. This was a spirit very unlike that which inspired Geoffrey of Monmouth’s mythical “History of the British Kings” with its tales of King Arthur, and William attacks Geoffrey and his legends with great indignation, calling the latter “impudent and shameless lies“. This striking illustration of his historic integrity won for him from Freeman the title of ‘the father of historical criticism’, and the compliment is not altogether undeserved.” http://www.newadvent.org/cathen/15634c.htm
But it doesn’t matter. Geoffrey had launched the legend of King Arthur upon the world and there was no turning back.