The O'Brien Clan

Ireland was one of the first countries in Europe to use a system of hereditary surnames. This is part of the legacy of Brian Boru.

As the population was growing larger in Ireland, the many ruling families needed a system to identify family members who would rule their clan, or group of families. To do this they selected the name of a successful family member, to which following members would add Mac for “son of” , or O’  or Ua which means 'grandson of'. This only occured in Ireland as in the rest of Europe names of places and territory were often used as surnames. It is interesting however that the Viking system of naming descendents follows this pattern of naming sons after fathers and grandfathers. 

From the 10th century on the O’Brien family name was born. 

Brian Boru, clans of Ireland

Brian Boru- Founder of the O'Brien Clan

Brian Boru assumed the title of High King peacefully in 1002. He remained High King until his death at the Battle of Clontarf 1014. One of the main changes brought about during his reign was the official adopting of surnammes by Gaelic clans.

The O’Brien name, Ua Briain (grandson of Brian), was adopted by his great-grandson Muirchertach, when he became High King of Ireland in 1101, in honour of him. It was also Muirchertach who gave the fortress at the Rock of Cashel, a seat long-held by O’Briens as King of Munster, as a gift to the Church.

Head of the O'Brien Clan Today

Conor Myles John O’Brien was born in Surrey, England on 17th July 1943. He is he youngest son of the 15th Baron of Inchiquin. The Prince of Thomond, Conor O’Brien is married to Josephine Bembaron and has one sister, Fiona. He became Chief of the O’Brien Clan on the death of his uncle Phaedrig, the 17th Baron on 20th May 1982. Some of the names he goes by are, The O’Brien, Prince of Thomond, Chief of the Name, The 18th Baron Inchiquin. He resides in his estate, Thomond House which lies on the grounds of Dromoland Castle. Dromoland Castle was the home of the O’Brien’s until 1962 when it was turned into a Luxury 5 star Hotel by Bernard McDonough. Conor O'Brien is the founder of the “O’Brien Clan Foundation”.

The O’Brien’s are destined for Ireland in 2014, which marks the 1000th anniversary of the Battle of Clontarf. This millenium will be celebrated in Ireland by O'Briens from all over the world.