Orlacan MacMurrough
Vitals
Family
About
Orlacan, or Orlaith, was a daughter of Diarmait Mac Murchada, King of Leinster, and about 1168 she was married to Donal Mor O'Brien, King of Thomond, in a political alliance that ran exactly parallel to her sister Aoife's marriage to Strongbow two years later. So this family descends from Diarmait twice, by two daughters: one into the Norman world through Strongbow and the Marshals, and one into the Gaelic royal house of Munster. Her mother is disputed between the sources.
Research notes
✓ FATHER CONFIRMED 23 Jul 2026 (all sources agree; Aynsley's DIB/Wikipedia/Geni check): ORLACAN (Orlaith), DAUGHTER OF DIARMAIT MacMURCHADA, KING OF LEINSTER (I99610); m. (arranged c.1168) DONAL MOR O'BRIEN, King of Thomond (I99642) - a political alliance parallel to her sister Aoife's marriage to Strongbow. So AYNSLEY DESCENDS FROM DIARMAIT, KING OF LEINSTER, BY TWO OF HIS DAUGHTERS - Orlacan (into the O'Brien royal line) and Aoife (into the Norman line via Strongbow, Marshal and Clare). MOTHER DISPUTED (father not): per the Dictionary of Irish Biography her mother was Diarmait's 1ST wife SADB NI FAELAIN (I99662, of the Ui Faelain), making Orlacan the HALF-sister of Aoife (whose mother was Mor Ni Thuathail); O'Hart instead gave 'dau. of O'Moore of Leix'; some trees make her Aoife's full sister. Sadb entered as mother per the DIB (grade ~ on the maternity). Direct ancestress. Added 23 Jul 2026.