Turlough O'Brien or Toirdhealbhach Donn Ó Briain was Lord of Thomond from 1499 to his death in 1528 and Chief of Clan O'Brien.[1]
Ó Briain, the son of Tadhg an Chomhaid Ó Briain, took over after the death of his uncle, Toirdhealbhach Óg Ó Briain.
In 1504, he supported Ulick Fionn Burke against Gerald FitzGerald at the Battle of Knockdoe and was defeated. In 1510, he defeated the forces of Gerald FitzGerald, who was invading Thomond with a large army, at Moin na m-brathar, near Limerick.
Toirdhealbhach Donn Ó Briain died in 1528 and was succeeded by his son, Conchobhar.[2]
Ó Briain married, firstly, Joan, daughter of Thomas Fitzmaurice, 8th Lord of Kerry. They had no known children. He married, secondly Raghnailt (died 1486),[2] daughter of Seán mac Conmara. They had children:[3]