MacMurrough, Dermot (1110–1171)

Irish ruler, king of Leinster 1126–66. He sought the help of the English king Henry II to return to power when he was deposed in a feud in 1166, and was instrumental in organizing the Anglo-Norman invasion of Ireland in 1170.

MacMurrough was ousted by the king of Connaught for eloping with Devorgilla, wife of Tiernan O'Rourke (or O'Ruark), King of Breifne. Living in exile in England, he was permitted by Henry II to recruit among the Normans of Wales, and persuaded their leader, Richard de Clare (2nd Earl of Pembroke, nicknamed ‘Strongbow’, c.1130–76) to launch an invasion. Strongbow took Waterford, married Dermot's daughter Aoife, and finally captured Dublin. MacMurrough has traditionally been regarded in Ireland as the archetypal traitor who helped instigate English rule, as for example in W B Yeats's play The Dreaming of the Bones 1921.