Uther becomes king after his brother's death and holds court in London. When the nobles present themselves before the new king, Uther falls for Igraine, the wife of Gerlois, the duke of Cornwall. She refuses to lie with him, infusing his desire for her even more. Determined to have her, Uther leads an army to ravage the ducal lands. Gerlois rides out with his men to meet the army and while he is away, Merlin magically alters Uther's appearance so that the king now resembles Gerlois. Uther enters Tintagel and lies with Igraine, who mistakes him for her husband. Thus, Arthur is begotten. The real Gerlois falls in battle, and Uther resumes his true shape and marries Igraine. In exchange for his help, Merlin demands the offspring of this union.
The remainder of his life is troubled by ill health and aggressive Saxons. Some sixteen years later he dies -- similarly to his brother -- by Saxon poison. Legend has it that he was buried besides his brother at Stonehenge.