Clan O'Brian

Brian Boru (Brian mac Cennetig or Brian Boroimhe in Gaelic) was one of Ireland's greatest leaders. A member of the Dal Cais (Delcassians) tribe, he was the brother of Mahon, who became King of Munster following the death of their father, Cenn-tig. At this point in Ireland's history, Viking invaders (or Norsemen) had a stranglehold on the island, while the native Irish either sided with the Norse out of fear or belonged to small kingdoms that fought among themselves. Mahon desired peace with the Vikings and attempted to attain it, but his younger brother Brian shared no such desire. In fact, after having witnessed the death of his mother and much of the Dal Cais tribe in a Norse raid while he was a child, Brian was a proponent of warfare with Vikings. When he was old enough, Boru broke away from his brother to wage guerrilla warfare on the Norse. A skilled tactician, he won many decisive victories that instilled fear in the enemy as well as their Irish allies. His attacks also helped to fuel rumours that there was a large, secret Dalcassian army. Boru's campaign gained much popular support and many Irishmen joined his cause, including his Brother Mahon, who renounced his truce with the Vikings. The combined forces were able to drive most of the Norse from Southern Ireland, including their leader Ivar (also known as Imar). .... more

Battle of Clontarf

Brian Boru, High King Of Ireland

• A1. Brian Boru High King Of Ireland, lvd:940/1014, m1. N., m2. Gormflaeth;
  • B1. [m1] Slani O'Brian, m. Sihtric , King of Dublin;  <==  Viking
  • B2. [m1] Teige O'Brian, d:1023;
    • C1. Toirrdelbach O'Brian, King of Munster and Ireland, d:1086;
      • D1. Muirchertach II O'Brian, King of Munster and Ireland, d:1119;
        • E1. Lafracoth O'Brian, m. Arnulf de Montgomerie;  <==  Montgomerie family
      • D2. Diarmait O'Brian, King of Munster, d:1118;
        • E1. Toirrdelbach O'Brian, King of Thomond, d:1167;
          • F1. Donnell Mor O'Brian, King of Munster, d:1194, m. Urlachan *;
            • G1. Mor O'Brian, d:1214, m. William de Burgh;  <==  de Burgh family
  • B3. [m2] Donnchad O'Brian, King of Munster, d:1064;
    • C1. Deabforgail O'Brian, d:1080, m. Diarmait MacMail, King of Ireland;
      • D1. Murchad, King of Leinster;
        • E1. Donnchad MacMurchada, King of Leinster, d:1151;
          • F1. Diarmait MacMurchada, King of Leinster, d:1171;
            • G1. Urlachan *, m. Donnell Mor O'Brian;
            • G2. Aoife (Eve), d:1177, m. Richard "Strongbow" de Clare;  <==  de Clare family