A distinguished Irish surname composed of elements meaning “people mighty” and “tribe rule”. Tuathal Mac Augaire, who belonged to the Uí Dúnlainge dynasty, was the name borne by a 10th century King of Leinster who died in AD 958, and of which Province the Ó Tuathail’s were one of the great clans. The O’Toole’s were remarkable for their unremitting resistance to Anglo-Norman attempts to conquer Ireland, from the late 12th century down to the end of the 17th century. They maintained a fierce independence and were a source of great fear to the inhabitants of Dublin and the surrounding areas, for almost four centuries.
The first use of the surname Ó Tuathail can be traced to Duncaon, grandson of Tuathal, and who died at Leighlin in 1014. The first recorded spelling of the name O’Toole is shown to be that of Archbishop Laurence O’Toole (1132 – 1182), which was dated in the “Medieval Ecclesiastical Records of Dublin”. *Leighlin it should be noted was the location for a church synod in AD 630, which decided that the Irish church should follow Roman as opposed to Celtic dating conventions for determining the date of Easter.