MacDonagh (MacDonogh), Michael (1699?–1746), catholic bishop, was a native of Coleraine, Co. Londonderry. His parents' names are unknown. He joined the Dominicans of St Mary's convent in Coleraine (c.1715–16) and subsequently left for Italy to study in Pesaro, before being sent to Rome (November 1718) to join the Irish Dominicans of SS Sixtus and Clement. These convents, along with Louvain and Lisbon, made up the three Irish Dominican colleges on the Continent. Fellow students there included Dr John Brett (d.1756), professor of philosophy and bishop of Killala and later Elphin, and Thomas Burke (qv) (de Burgo), bishop of Ossory (1759–76) and author of a history of Irish Dominicans (1762). In later life, MacDonagh sent numerous gifts to the convents, including cheese and butter, a sacristy clock, and an Irish harp. He continued his studies at the College of St Thomas in Naples and was ordained (1723) in the small papal state of Beneventum by the bishop, Pietro Orsini, a fellow Dominican and the future pope Benedict XIII. Initially ordered to return home on an Irish mission, he was appointed to teach scripture at SS Sixtus and Clement (1725). He also acted as Roman agent for the English Dominicans (1726), visited Ireland (1727), and became the Roman agent for the Irish provincial (1727). He and Bonaventure O'Gallagher, OFM, of St Isidore's, presented themselves to Propaganda as the Roman agents for all the religious of Ireland (1728).
MacDonagh arranged for translation into Italian of a book on St Patrick's purgatory (1726), written by his uncle Dominic Brullaughan (Dominick O'Brullaghan; Daimnic Bán Ó Brolcháin, d. 1747), OP, of Coleraine. Famed in folk legend as ‘An bráthair bán’ (the white or fair brother), Brullaughan travelled on mission disguised as a sheep dealer. In 1728 the Irish controversalist Sylvester Lloyd (qv) discussed a book proposal with MacDonagh, who subsequently mentioned it to both the pope and James III. He was by this time mediating between the pope and king, not least on James's financial and matrimonial problems. He arranged, too, for a copy of Gulliver's travels by Jonathan Swift (qv) to be sent to the king. With these connections, as James still retained the right of nomination to all Irish sees, it is hardly surprising that MacDonagh was consecrated bishop of Kilmore (12 December 1728) at the age of 29. Shortly afterwards, he was given a title of nobility in Beneventum, made a domestic prelate, and named assistant to the papal throne (1729). He was appointed, too, as confessor to the young ‘Bonnie Prince Charlie’ (Charles Edward Stuart) and might have advanced still further in Rome, but for the death of the pope (1730).
MacDonagh finally left for Ireland (1730), arriving in time to witness the resignation of Cornelius Nary (qv) from the parish of St Catherine in Dublin. Kilmore had been without a bishop for sixty years, and the appointment of the young bishop without Irish experience caused some furore. As bishop (1728–46), he divided his time between the diocese and Dublin, where he lived with the Dominicans in the convent of Channel Row (now North Brunswick St.). This, too, brought criticism, but made escape from the penal laws much easier. He was also involved in the ongoing disputes between secular and regular clergy, generally taking the side of the religious orders. Another controversy involved the installation of his double first cousin, John Brullaughan, parish priest of Coleraine, as dean of Derry (1737). Far more significant, on 6 June 1739 MacDonagh and John Fottrell, provincial of the Irish Dominicans, were arrested as spies while travelling in Toomebridge, Co. Antrim. The two had in their possession extensive papers identifying their positions, the bishop's alias as ‘Mr Clarke’, and details of Dominican affairs. Among the material seized was MacDonagh's lampoon of pretended converts to protestantism. Brought to Springhill, in the parish of Moneymore, for examination and imprisonment, the two escaped. With a reward of £200 offered for his capture, MacDonagh had sailed in disguise to the Continent by the end of 1739 or early 1740. Arriving in Rome, he met Pope Benedict XIV to discuss Irish concerns, including the challenge of protestant charter schools.
MacDonagh returned again to Ireland by way of Livorno (Leghorn), Paris, and Brussels. In Brussels, he and three other Irish bishops drafted a letter to the pope outlining the financial difficulties of maintaining the surplus of priests in Ireland (12 May 1741). Back in Ireland, the authorities were well informed of the bishop's whereabouts and identity. While they frequently turned a blind eye to catholic clergy, MacDonagh, accused of treason by his enemies, again went on the run, changing houses twelve times in two months. His health had begun to reflect the strains of this fugitive existence. Having made a will (12 September 1746) as a precaution before travelling to the Continent for his health, he died in Lisbon on 26 November 1746. He was buried in Corpo Santo, the church of the Irish Dominicans, and a monument was erected to him. MacDonagh's cousin Dr Patrick Bradley (Brullaghan, Brolcan, Brolaghan), who also completed his studies at SS Sixtus and Clement, was chaplain to the Sardinian ambassador in London (1730–51) and was bishop of Derry (1751–2).