According to a tradition not found in Malory, this tower kept falling down. Vortigern’s astrologers told him that to stand, the masonry required the blood of a fatherless child. Vortigern found the young Merlin, who had been engendered by a devil and thus could be considered fatherless, but Merlin saved himself by making explanations and predictions which were found true.
According to Merlin’s statement, a lake was discovered beneath the tower. There a red dragon (symbolizing Vortigern) and a white dragon (symbolizing Pandragon and Uther, the two sons of King Constans, whom Vortigern had murdered to gain his power) fought to the death. The white dragon killed the red, but soon afterward died itself. The sons of Constans burned Vortigern’s Tower after they killed him.
Clues in the Vulgate led Phyllis Ann Karr to believe that Vortigern’s Tower was near Winchester. Because of the name, Din Guortigern, mentioned by Nennius and identified by one Mr. Pearson as on the Teviot River, is another contender.