Diarmait Mac Murchada

Diarmait Mac Murchada , anglicised as Dermot MacMurrough or Dermod MacMurrough , was a King of Leinster in Ireland. In 1167, he was deprived of his kingdom by the High King of Ireland Ruaidri Ua Conchobair. The grounds for the dispossession were that Mac Murchada had, in 1152, abducted Derbforgaill, the wife of the King of Breifne, Tiernan ORourke . To recover his kingdom, Mac Murchada solicited help from King Henry II of England. In return, Mac Murchada pledged an oath of allegiance to Henry, who sent troops in support. As a further thanks for his reinstatement, Mac Murchadas daughter Aoife was married to Richard de Clare, the 2nd Earl of Pembroke . Henry II then mounted a larger second invasion in 1171 to ensure his control over Strongbow, resulting in the Lordship of Ireland. Mac Murchada was later known as Diarmait na nGall .

Mac Murchada was born around 1110, a son of Donnchad mac Murchada, King of Leinster and Dublin. His fathers grandmother Dervorgilla was a daughter of Donnchad, King of Munster and therefore she was a granddaughter of Brian Boru. His father was killed in battle in 1115 by his cousin Sigtrygg Silkbeard, king of the Dublin Vikings, and was buried by them in Dublin along with the body of a dog, considered to be a huge insult.

Source: Wikipedia