Dermot McMurrough or Diarmiud mac Murchada both: dûr´mət məkmŭr´ə [key], 1110–71, Irish king of Leinster. He became involved in a complicated feud, partly because he abducted a neighbor's wife, and in 1166 was defeated and banished by the High King Rory O'Connor . Dermot appealed for help to Henry II of England, who refused him direct support but allowed him to enlist a force led by Richard de Clare, 2d earl of Pembroke , and other Norman barons in Wales. After Pembroke had invaded (1170) and won much of E Ireland, including Dublin, he married Dermot's daughter, Eva. He was a patron of the compilation of the valuable Irish manuscript, the Book of Leinster.
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