Diarmait Mac Murchada (Modern Irish: Diarmait mac Murchadha or Diarmaid mac Murchadha), anglicized as Dermot MacMurrough or Dermod MacMurrough (1110–1 May 1171), 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 MacMurrough had, in 1152, abducted Derbforgaill, the wife of the King of Breifne, Tiernan O'Rourke (Irish: Tighearnán Ua Ruairc). To recover his kingdom, MacMurrough solicited help from King Henry II of England. In return, MacMurrough pledged an oath of allegiance to Henry, who sent troops in support. As a further thanks for his reinstatement, MacMurrough's daughter Aoife was married to Richard de Clare, the 2nd Earl of Pembroke (nicknamed "Strongbow"). Henry II then mounted a larger second invasion in 1171 to ensure his control over Strongbow, resulting in the Lordship of Ireland. MacMurrough was later known as Diarmait na nGall (Irish for "Diarmait of the Foreigners").
Read more about Diarmait Mac Murchada: Early Life and Family, King of Leinster, Church Builder, Exile and Return, Death and Descendants