Gorlois

In Arthurian legend, Gorlois (Welsh: Gwrlais) of Tintagel, Duke of Cornwall, is the first husband of Igraine. whose second husband is Uther Pendragon. Gorlois is the father of Morgan le Fay, Morgause, and Elaine of Garlot.

Igraine and Gorlois in Władysław T. Benda's illustration for Uther and Igraine by Warwick Deeping (1903)

Gorlois's name first appears in Geoffrey of Monmouth's Historia Regum Britanniae (c. 1136),[1] in which Uther falls in love with Igraine and wars with Gorlois to get to her. Uther asks for Merlin's aid in pursuing her, and Merlin concocts some drugs that disguise Uther in the form of Gorlois. In this form he approaches his love and they sleep together, conceiving Arthur. Unbeknownst to either of them, the real Gorlois has been killed in his castle that very night. Eventually Igraine is convinced to marry Uther.

Later treatments, such as the Vulgate Cycle and Thomas Malory's Le Morte d'Arthur. expand on this outline by having Gorlois's daughters married off to vassals of Uther's: Elaine to King Nentres of Garlot, Morgause to King Lot of Orkney, and (after she has received an education in a convent) Morgan to King Urien. Arthur is spared any knowledge of his halfsisters after he is whisked away by Merlin to be raised by Sir Ector.