Creagh, Peter (‘Piers Crevens’) (c.1640–1705), catholic archbishop of Dublin, was born into a highly reputable Limerick family. He was the great-nephew of Richard Creagh (qv), archbishop of Armagh, and the nephew of Dr John Creagh (d. 1663), vicar general of Limerick and private chaplain to Pope Alexander VII. Educated at the Jesuit college at Poitiers by his uncle Edward Creagh, Peter entered the Irish college at Rome in 1660, where he studied under Dr John Creagh; his two brothers John and Bartholomew also attended the college. He won recognition for his conduct, discretion, and intellectual ability. Ordained in February 1666, he obtained his doctorate and left for Ireland, where he served on the mission for three years before returning to Rome as agent of the Irish bishops in place of John Brenan (qv). He is known to have been fluent in Italian, Latin, French, English, and Irish. In September 1671 Oliver Plunkett (qv) described him as a man of average height with a long oval face and reddish brown hair and beard.
On 22 April 1676 Creagh was appointed bishop of Cork and Cloyne, and he was consecrated on 26 May at the church of St Isidore, Rome. He made the journey back to Ireland with Patrick Tyrrell (qv), who had been recently elevated to the see of Clogher. At thirty-six he proved more than capable of withstanding the rigours of pastoral life, travelling through his diocese confirming, baptising, and stamping out abuses. According to Archbishop Plunkett , he was ‘a learned, pious and sweet bishop’. In 1679 accusations of treason were laid against him by David Fitzgerald, a witness in the investigations into the popish plot. He took refuge for a time with his brother John at Killaloe, near Limerick, but he was captured in March 1680 and imprisoned at Limerick and Dublin; he finally stood trial in August 1682. By this time, however, the popish plot had run its course. Some of his accusers failed to appear; another withdrew his evidence. His claim of innocence seemed to be reinforced, supernaturally, by the collapse of the courthouse roof, which buried his accusers and prosecutors, and narrowly missed the bench; Creagh's escape unscathed became the talk of catholic Europe and was later celebrated by the poet Diarmaid mac Sheáin Bhuí Mac Cárthaigh (qv). The case against him eventually dissolved and Creagh was acquitted.
At the succession of James II (qv) Creagh and his fellow prelates availed themselves of their new-found freedom to improve the condition of the Irish church. Creagh attended the provincial synod convened by Archbishop Brenan in Cashel and later received a pension of £150 from the king. In October 1690 the Jacobite government dispatched him to seek assistance from Louis XIV after the defeat of King James's forces at the Boyne. Louis rewarded him with a present of costly vestments and religious objects. He is recorded as being at James's court at St Germain early in 1692, and in November of that year James nominated him to the archbishopric of Dublin; he was provided to the see on 9 March 1693. It was impossible for him to return to Ireland, so Creagh chose to go to Strasbourg as auxiliary to the cardinal-bishop of Strasbourg, from where he governed his diocese through his vicars general Dr John Dempsey, parish priest of St Michan's, and Father Edward Murphy, parish priest of St Audoen's.
Creagh died 25 July 1705, after a long illness, and was buried in the choir of St Stephen's church, Strasbourg. The sumptuous monument erected in his memory was destroyed during the French revolution. Much of Creagh's correspondence remains from his time as agent of the Irish bishops in Rome. An inventory of his extensive library shows him to have had a passionate interest in the Classics, the Greek language and its antiquities, canon law, and jurisprudence, as well as philosophy, history, magic, mathematics, and astronomy.