The history of the Celtic peoples goes back some thousands of years. At one time all of Europe was Celtic. England was ruled entirely by Celts . Eventually the Romans, Angles and Saxons came and pushed the Celts to the north and west. One of the great Celtic events of history was the Fifth-Century battle between King Arthur and his Celtic army against the dark pagan hordes in England ( as the Celts termed the non-Celtic peoples ). The Celts considered King Arthur's loss to be the death of civilization. King Arthur himself remains an important figure in Celtic legend. The original historic story is now much embroidered with medieval knights and traditions.