Gorlois' name first appears in Geoffrey of Monmouth's Historia Regum Britanniae (c. 1136), 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. As Gorlois, he approaches his love easily 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.