MacDuane, Thaddeus (Tadhg Mac Dubháin) , (d. 1608), Dominican priest and prior of Sligo, was a native of Connacht. While little is known of his early career, his personality manifested itself as that of a leader of great moral stature, who towered above the growing desolation of Hibernia Dominicana. He thrice visited Rome, being one of a small number of sixteenth-century Irish Dominicans (including his predecessors David Brown (qv), Quentin Cogly (qv), Quentin O'Higgins (qv), Eugene O'Harte (qv), William MacAneaney, and Cormac Ó Fergusa (qv)) known to have gone there. His first journey to Rome was made when he was prior of Holy Cross, Sligo, in the late spring of 1577. On that occasion he submitted three petitions to the Apostolic Datary, seeking the restoration of Dominican pastoral rights, contested by parochial clergymen and other clerics (regular and secular); the ending of vexations from laity, nobles, and peasants alike in respect of the priory church and property; and permission to obtain relics and to publish indulgences, especially for the patronal feasts of the finding and exaltation of the Holy Cross, on account of the image of the crucified one venerated in their church. The priory church had already been designated as the cathedral of Elphin by Bishop Andrew O'Crean (qv). MacDuane disclosed that the Sligo community, entirely bereft of money, was desirous of repairing much of the dilapidated fabic of their church and conventual buildings: the dormitory, cloisters, adjacent rooms, the undercroft of the church, external walls, and outbuildings. On the question of funeral offerings, donations, tithes, and income deriving from the property of founders and benefactors, Pope Gregory XIII upheld the rights of the Dominicans, thus recognising and easing the pressing problem of lay and clerical intrusion on their rights and material resources. The texts of the petitions provide an illuminating commentary on contemporary Irish catholicism as well as the world of the Sligo Dominicans and the difficulties they suffered.
A letter written by MacDuane from the Dominican house of Coleraine (1 August 1593) to Hippolitus Maria Beccaria, the master general of the order, was taken to Rome by MacDuane's trusted friend and protector, James O'Hely, archbishop of Tuam (1591–5). MacDuane's immediate purpose in writing to Beccaria was to legalise his own position as vicar of the Irish province. He had been appointed to this office by the dying provincial, Eugene MacHugan or MacEgan (whose Irish surname, Mac Aodhagáin, was that of the distinguished Connacht brehon family of Uí Maine) on account of the continuing decline of the province and the very disturbed times. The letter touched on the increasing ferocity of religious persecution: the order was threatened with extinction because so many friars had died; so few brethren remained that they could scarcely ensure the viability of four convents; for many years the Irish Dominicans had been unable to assemble to elect a common superior owing to the vigilance of their persecutors, backed by the authority of the English queen, the lack of a safe meeting-place, their distance from each other, and their deplorable plight. MacDuane stated that he had encountered many disciplinary problems: some Dominican priests were living outside their houses, others evading ecclesiastical supervision, and others had laid aside the religious habit through fear and had incurred excommunication. For these MacDuane sought absolution from what canonically and technically was ‘apostasy’. He referred to houses of reformed and unreformed brethren and requested that the unreformed be prohibited from electing their own independent vicar. There were problems too with the bishops of the northern province, especially Redmond O'Gallagher (qv) of Derry (1569–1601) and Conor O'Devany (qv) of Down and Connor (1583–1612), who sought to restrict the rights of Dominicans by abolishing religious exemption and bringing their houses and activities under episcopal control. As his own authority would soon expire, he pressed for the appointment of a new provincial to deal with the problems outlined. MacDuane was twice reappointed vicar of the province by Master Beccaria (13 April 1594 and 28 March 1597).
MacDuane's signature, with those of the Franciscan and Carmelite provincials, appeared on a document dated from Donegal on 13 June 1600 that sought the appointment of proctors for the diocesan chapter of Raphoe. MacDuane was again named vicar of the Irish Dominican province on 20 October 1608 by Master Agostino Galamini, but he died in that very year and was buried at Holy Cross. Thaddeus MacDuane was the most important Dominican superior to preside over the remnant Irish Dominican province. Through his personal influence, particularly in Connacht and Ulster, he saved it from total extinction. He is said to have addressed the critical problem of recruitment by entrusting novices for training to the Franciscans at Donegal, and had the aspiration to found a house of studies in the Low Countries, which came to fruition as the college of Holy Cross in Louvain, c.1626.