Ua Conchobair, Tommaltach (c.1150–1201), bishop of Elphin and archbishop of Armagh, was son of Áed and grandson of Tairdelbach Ua Conchobair (qv), king of Connacht, and became bishop of the O'Connor-dominated diocese of Elphin c.1174. There are some indications that he travelled to Rome and to the royal court to receive confirmation of his election under the terms of the second synod of Cashel. He also appears to have been responsible for the foundation of a Cistercian house in Athlone.
In 1179 Ua Conchobair was one of the bishops who attended the council called by the papal legate, Lorcán Ua Tuathail (qv), archbishop of Dublin, to whom he gave his complete support. Ua Tuathail brought Ua Conchobair with him when he travelled to Armagh in early 1180 to settle the issue of the succession to the archbishopric. There had been several short-lived archbishops in the previous decade; the legate, who appears to have had some concerns about the strength of the reform movement in Armagh, installed Ua Conchobair as the new archbishop. As long as the legate was in the province of Armagh, Ua Conchobair's claims to authority were respected, but when Ua Tuathail left to negotiate between Henry II (qv) and Ruaidrí Ua Conchobair (qv), king of Connacht, the new archbishop had to undertake the traditional ceremonies involved with his recognition as the coarb of Patrick. This serves to underline the difference between the positions of archbishop and coarb in the late twelfth century, as Ua Conchobair was not accepted in Ulster till late 1181.
His heritage and links to Connacht appear to have limited his abilities to undertake the role of peacemaker within Ulster, although he was often involved in the negotiations to establish peace in Connacht from the mid 1180s. In 1184 there was an abortive attempt to replace him with Máel Ísu Ua Cerbaill, bishop of Airgialla (Clogher); but although this challenge was ultimately unsuccessful, Ua Conchobair was not restored to his see till 1186. He appears to have maintained good relations with the Anglo-Normans and may have travelled to Dublin in 1181 to meet with Hugh de Lacy (qv) and perhaps again in 1185 to meet John (qv), lord of Ireland, while he was in Dublin. He also had to deal with the efforts of John de Courcy (qv) to expand his lordship into Armagh, which led to a decade of wars between de Courcy and Ruaidrí Mac Duinn Sléibe, causing widespread devastation of the lands of the archbishopric. Despite this, Ua Conchobair joined with de Courcy in commissioning a Life of St Patrick that served to emphasise Armagh's claims to the primacy of Ireland in the face of the growing power of Dublin.
Ua Conchobair's most lasting achievement was to regain control of the diocese of Louth at the synod held in Dublin (1192), which returned the diocese of Armagh to the boundaries set out at the synod of Ráith Bressail. Continual warfare in Ulster and the need to cement his control over his expanded diocese led Ua Conchobair to spend much of the last five years of his life in Drogheda. While the majority of the documents of his episcopate have been lost, several letters from Innocent III survive, dealing with issues such as disputed elections, support for the Arrouasian canons, and the canonical position of women. Ua Conchobair died in 1201 en route to Armagh and was buried in the Cistercian abbey of Mellifont.