Vortigern

Vortigern hires Saxon mercenaries to hold off the Picts and cannot get rid of them. Trying to build a fortress, he finds the walls fall down every night; his advisers tell him to sprinkle the foundations with the blood of a boy who has no father. The boy they bring is Merlin, who tells them instead to dig, and beneath the foundations they find a pool, and in the pool two sleeping dragons, red and white, who wake and fight — and Merlin explains that the red is the Britons and the white the Saxons, and delivers the prophecies. It is the moment the legend acquires a prophet.