O'Brien, Terence Albert (Muiris Ó Briain Aradh) (1601–51), catholic bishop of Emly and Dominican provincial, was born at Tuogh (Towerhill), in the parish of Cappamore (diocese of Emly), Co. Limerick, the son of Murchadh O'Brien Aradh. Both his parents were of the noble family of O'Brien Aradh which claimed lineal descent from Brian Bórama (qv). His forebears included a number of ecclesiastics: Maurice MacBrien, bishop of Emly (1567–86) banished from Ireland by Queen Elizabeth, Turlough (Terence) O'Brien, bishop of Killaloe (1554–69), and Murchadh (Murrough, Maurice) O'Brien Aradh, bishop of Killaloe (1576–1613). At the time of his birth, the O'Brien family still possessed an estate of more than 2,500 acres centred on Tuogh, but this was expropriated in the 1650s under the Cromwellian confiscations.
O'Brien entered the Dominican order about 1621 at St Saviour's, King's Island, Limerick, where his uncle Bernard O'Brien was prior. The house had been founded in 1227 by an ancestor of O'Brien, Donnchad Cairprech Ó Briain (qv). He received the name Albert as his name in religion. Subsequently he studied in Spain, in the imperial city of Toledo, as attested by Father Master Reluz OP, his lector of philosophy. He was elected prior provincial at the Black Abbey, Kilkenny, in 1643, and attended the general chapter of the Dominicans at Rome (1644), at which he was made master of sacred theology. He returned to Ireland via Lisbon, where he made visitations to the Irish Dominicans of Corpo Santo College, and to the Irish nuns of Bom Sucesso at Belem. His library as provincial contained the works of St Thomas Aquinas, Thomas Cajetano, Baronius, Sixtus Senensis, and Huze, and the Concilia generalia, all indicative of his intellectual formation at a time when philosophical and theological studies had reached new heights in leading European catholic centres. O'Brien was named co-adjutor bishop of the rural diocese of Emly, with right of succession to Bishop Maurice O'Hurley (1623–46), by Innocent X on 11 March 1647 (by which time news of O'Hurley's death had still not reached Rome); he was consecrated on 2 April 1648 by GianBattista Rinuccini (qv), archbishop of Fermo and nuncio extraordinary, at Waterford cathedral.
The struggle for full freedom to practise the catholic religion had disclosed serious differences and divisions in the 1640s between Old English and Gaelic Irish catholics. O'Brien unshakeably supported Rinuccini's position, seeking a settlement that would guarantee without compromise the ancient rights of the catholic church. His own order divided on the same racial lines as the generality of Irish catholics. He was one of several Dominicans, including Dominic Burke (qv), Edmund O'Dempsey (qv), bishop of Leighlin, Oliver Darcy (qv), bishop of Dromore, and Thomas Coursey, former prior of Kilkenny and Limerick, who held the offices of preacher and chaplain-in-ordinary to the confederate catholics, and who were influential members of the general assembly of the confederation of Kilkenny (1642–9).
With the break up of the assembly of confederate catholics, O'Brien went to Connacht and from Galway he wrote to Propaganda Fide (29 March 1651) as the Cromwellians advanced on Limerick. The letter clearly displayed his distress and depression at the catastrophes which had befallen Irish catholics, yet expressed the hope that their political and religious situation might somehow be salvaged. When the parliamentarian army reached the walls of Limerick in June 1651, the bishop of Emly was within, exercising moral leadership in repelling the siege. On the fall of the city on 29 October 1651, Bishop O'Brien, who was known to have called for the strongest resistance, was arrested, together with Major-General Purcell, in the ‘plague house’ where he was tending the sick, and was chained hand and foot. O'Brien's trial by court martial followed immediately and he was hanged in odium fidei on 30 October 1651 by Henry Ireton (qv), commander of the Cromwellian forces. Denis O'Hanraghan OP (author of the lost manuscript entitled ‘Rosetum praedicatorium’) ministered to him before his execution; a version of the substance of the bishop's last speech and prayer has come to light. His body was left hanging for three hours and subjected to a barbarity and violence that did not mark other executions; his head was severed from his body and spiked on the river gate of Limerick. As a catholic bishop, he was viewed as a symbol of the ‘popery’ so openly hated by Ireton and the puritan parliamentarians. He was the third catholic bishop to be executed in Ireland under puritan rule; another Dominican, James Wolfe, several times prior of Limerick, was taken while celebrating mass and was summarily hanged in the city in 1651.
Bishop Terence Albert O'Brien belonged to a family of Gaelic chieftains (as did also bishops Maurice O'Hurley and Edmund O'Dwyer (qv)) in transition to the status of landed Irish aristocracy. He was a man of immense integrity, whose vision of a new Irish order was never dimmed. He did not flee defeated Limerick in disguise, as did his cousin Bishop O'Dwyer of Limerick. He sought no pardon, nor did he surrender to the enemy, who had long since decided on his execution. He was declared a beatified martyr by Pope John Paul II on 27 September 1992.