Medieval romances make Morgause the wife of King Lot of Orkney and mother of several knights, including Gawain. In influential versions, Arthur unknowingly fathers Mordred with her before learning that she is his sister or half-sister.
This is a modern elaboration of traditions that vary considerably between texts. Morgause links Arthur’s family, the Orkney faction and the conception of Mordred, making kinship central to the kingdom’s collapse. Morgause was born in Britain (legendary).
Mary Stewart’s The Last Enchantment places Morgause within the dangerous family history that shadows Arthur’s apparently successful reign: as Arthur’s half-sister and Mordred’s mother, her actions turn kinship into a source of future political catastrophe. The Wicked Day returns to her influence through Mordred’s upbringing in Orkney, showing how the resentments, prophecies and ambitions surrounding Morgause shape the son who will eventually be drawn into Arthur’s final conflict.