The O’Brien family are directly descended from Brian Boru (Bryan Boru). The name Ua Briain (grandson of Brian) was adopted by his great-grandson Muirchetach when he became High-King of Ireland in 1101, in honour of him. The chief of the Dalcassian Council today is Conor Myles O’Brien, Prince of Thomond. The O’Briens are one of the Great historic Irish families and their heartlands were in Thomond.They became earls of Thomond and Inchiquin. They were famed as soldiers the most famed being Brian Boru.

Additional O’Brien names include O’Briain, O’Bryan, O’Brein, O’Brian and Bryant originating from Clare (primarily), Limerick, Tipperary and Waterford.The clans of the Dal gCais acknowledge Sir Conor O’Brien, Lord Inchiwuin as Chief of the Dalcassian Council.

O'Brien Clan, Brian Boru, Bryan Boru

Conor Myles John O’Brien was born in Surrey, England on 17th July 1943. He is he youngest son of the 15th Baron 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 Dromolan 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 nationally and internationally by O'Briens all over the world.