Maeve (or Medb, if one is Irish) is the "last and haughtiest" of the six daughters of the High King of Ireland (Fraser, 15). Her first marriage was to Conor MacNessa, King of Ulster. She acquired the kingdom of Connaught through her second marriage. Her third, and most famous, marriage was to Ailill of Leinster. A comparison of the worldly goods each brought to the marriage led to the Cattle Raid of Cooley, and an incredibly bloody war with Ulster and its champion, Cu Chullain.
After this war, Maeve left Ireland temporarily, settling in England while tempers cooled and memories faded. There she began teaching a select few students in the magical arts she had learned at her father's court in Tara. These included both Druidical and Wizarding techniques, and she made no distinction between them. Among her students was Rowena Ravenclaw, one of the last members of Scotland's Druid families. She stayed in England until Athelred II named Dunstan, Archbishop of Canterbury, to the Witenagemot. She returned to Ireland to protest this move, retiring quietly (for her) to Connaught to found a school of magic. Despite her antipathy for the Church, and for Muggles (in the ancient sense), she also has little patience for the small minded among magical folk, and therefore, does not get on particularly well with families such as the Blacks and the Slytherins.
Maeve has yellow hair, often wears purple robes embroidered with gold, and is usually accompanied by one or more tawny owls riding on her shoulder(s). She is credited with the idea of asking these birds to carry messages to her friends and allies.