Morgause

The name of a witch in Arthurian romance. Morgause, Queen of the Orkneys, is Arthur's half-sister with whom, in Thomas Malory's 15th-century compilation 'Le Morte d'Arthur', he engages in a brief affair, producing Mordred. She is also the mother of Gawain and Gareth. The earliest forms of her name are Orcades - the earliest known name of the Orkney Islands, probably derived from Celtic *forko- meaning "piglet" (cf. Orcadia) - and Morcades. Orcades probably mutated into the forms Morcades and Morgause through confusion with Morgan 2.