Mac Cathmhaoil (Mac Aingil), Aodh (MacCaghwell, Hugh; Cavellus, Hugo) (1571–1626), Franciscan scholar and catholic archbishop of Armagh, was born in Downpatrick, Co. Down, a member of a Gaelic learned family that was originally located in Clogher, Co. Tyrone. Given his proficiency as a poet, it is possible that he studied at a local bardic school before travelling to the Isle of Man for further education. On his return to Ireland he was employed by Hugh O'Neill (qv), as tutor to his two sons, Henry and Hugh. It is commonly assumed that Mac Cathmhaoil, more popularly known as ‘Mac Aingil’, is the person Sir John Harington (qv) referred to as a ‘younger scholar’ in his description of a visit to O'Neill's castle in Dungannon in 1599. It is also assumed that he travelled to Spain with Henry (19 April 1600) when the latter was sent as a hostage to Philip III against the promise of Spanish military aid to O'Neill. While not disputing Mac Cathmhaoil's presence in the university of Salamanca by 1600, Noel Ó Gallchóir notes that none of the contemporary documents concerning Henry's journey to Spain mentions Mac Cathmhaoil, and that he would have needed a much longer period of study to have obtained a doctorate by 1605. What is not in dispute, however, is that he joined the Franciscans in Salamanca in 1603 and was ordained priest prior to his appointment as preacher to Henry O'Neill's Irish regiment in Flanders on 23 December 1605, and later as chief chaplain.
Having spent some time lecturing in theology in the university of Salamanca, Mac Cathmhaoil cooperated with Florence Conry (qv) in the establishment of the Irish Franciscan College of Louvain in 1607. He took up residence as professor of theology in June of that year and succeeded Donagh Mooney (qv) as guardian (1610), a position he held on a number of occasions. On Henry O'Neill's death in 1610 he was reappointed chief chaplain to John O'Neill's regiment, a post he held till his death. From 1609 onwards he was involved in negotiations with William Trumbull, the English government's representative in Brussels, on behalf of the exiled earl of Tyrone. These negotiations proved fruitless, and on 3 July 1614 Robert, earl of Somerset, ordered Trumbull to break off all discussions with the Irish friar. Mac Cathmhaoil was also busy promoting Irish interests with Guido Bentivoglio, the papal nuncio in Flanders during this time. It would seem that he also kept the king of Spain up to date on Irish affairs, as the English spy John Bath wrote in 1613 that he advised the king to pay no attention to any information he might hear from Conry or Mac Cathmhaoil. When the Irish Franciscans acquired a piece of land in May 1616 to build a permanent college and chapel, the burden of seeing the project through to completion fell on Mac Cathmhaoil. It was also during his tenure of office that the Franciscan mission to Scotland was established. Mac Cathmhaoil was far from an enthusiastic supporter of the project, however, and it was only on the express order of the pope in 1618 that he agreed to release a few friars from the Louvain community to go to the Highlands.
In 1618 Mac Cathmhaoil published a religious treatise on the sacrament of penance on the friars’ printing press in Louvain, Scáthán shacramuinte na haithridhe (‘Mirror of the sacrament of penance’). Written primarily for the laity, this work is an explanation of the council of Trent's teaching on the sacrament of penance, but with particular application to Irish conditions. Writing in a lively and lucid style, Mac Cathmhaoil took pains to elucidate his doctrinal content with vivid examples and showed himself to be a master of the rhetorical devices associated with baroque writing. Of particular interest is the fact that he referred to Ireland as a ‘catholic nation’, while at the same time calling James I ‘our noble illustrious king’. Indeed, the last section of the work dealing with indulgences was little more than a pretext for providing Irish catholics with valid reasons for accepting James I as their legitimate sovereign. While not expressly citing these terms, Mac Cathmhaoil deftly availed of the distinction between subjective and objective heresy to distance the king from Luther and Calvin. Furthermore, through a highly selective use of James's Praefatio monitoria (1609), Mac Cathmhaoil sought to demonstrate that the king's own religious beliefs were both explicitly and implicitly in accord with catholic teaching. With the death of O'Neill in Rome in 1616, the best way forward for Irish catholics was to seek an accommodation with James. If Ireland provided a striking exception to the principle cuius regio eius religio, Mac Cathmhaoil's treatise on indulgences was a most interesting effort to solve this dilemma, and added a highly charged political dimension to what appeared to be merely a religious text. A further indication of the ideological thrust of this work is found on the title page, where the author is described as a lecturer in theology a coláisdi na mbráthar nÉirionnach a Lobháin (‘at the college of the Irish friars in Louvain’), the adoption of the neutral geographic marker Éirionnach signifying an attempt to break down ethnic barriers and reconcile those of Gaelic descent and those of Anglo-Norman descent under one faith, one culture, one king. In addition to his prose writing, Mac Cathmhaoil was a talented, if not prolific poet. His justly celebrated nativity poem, ‘Dia do bheatha, a naoidhe naoimh’, has much more in common with Crashaw than with Milton, and derives much of its inspiration from such counter-reformation spiritual classics as Louis de Puente's Meditaciones de los misterios de nuestra santa fe (Valladolid, 1605).
Though mistaken in his belief that John Duns Scotus was both an Irishman and a native of Co. Down, Mac Cathmhaoil was recognised by his contemporaries as an outstanding Scotistic scholar. In 1620 his edition of the commentaries of John Duns Scotus on the Book of Sentences by Peter Lombard (qv) was published in two massive volumes in Antwerp. Further works on Scotus followed over the next five years such as Apologiam apologiae supradictae pro Scoto scriptae (Paris, 1623) and Quaestiones in metaphysicam (Venice, 1625). With due acknowledgements to his predecessor, Luke Wadding (qv) incorporated these works in his edition of Scotus in 1639, an edition that initiated a new epoch in the history of Scotism and that was not superseded till the 1950s. While some commentators hold that Mac Cathmhaoil was Ireland's greatest ever theologian, a thorough assessment of his contribution to theology still remains to be undertaken.
On 29 May 1621 Mac Cathmhaoil was chosen as one of the definitors general of the Franciscan order. One of his initial challenges was to undertake the reform of the Franciscan friaries in France, in particular that of the grand couvent in Paris. In 1623 he was summoned to Rome to aid in the governing of the Franciscan order and to teach theology in the convent of Ara Caeli. With Luke Wadding he was instrumental in procuring Collegio Sant’ Isidoro in Rome for the theological training of Irish Franciscans and he also helped in establishing a college for the training of Irish secular clergy. He was consulted by the Vatican on the filling of vacant dioceses in Ireland; his own name did not appear on a list of twenty-two suitable candidates that was compiled early in 1625. On the death of Peter Lombard, titular archbishop of Armagh, at the end of that year, Luke Wadding and the earls of Tyrone and Tyrconnell strongly urged Mac Cathmhaoil's candidacy. Despite strong opposition from the French government because of his Spanish sympathies, and from the papal nunctio in Brussels who felt that it was already excessive to have two of the four Irish archdioceses in Franciscan hands, Mac Cathmhaoil's supporters prevailed. Appointed on 27 April 1626, he was consecrated on 7 June. While preparing to return to Ireland he fell suddenly ill and died of a tertian fever 22 September 1626 in the infirmary of Ara Caeli, and was buried in the chapel of St Isidore's. His memorial monument was erected by John O'Neill, earl of Tyrone.
A portrait by an unknown artist of the Rembrandt school is now in the possession of the Irish Franciscan Province of Ireland. In 1672 Fra Emmanuele di Como painted a fresco of Mac Cathmhaoil in his episcopal robes in the Aula Maxima of St Isidore's College, Rome. The earliest biography of Mac Cathmhaoil is found in Nicolaus Vernulaeus, Panegyricus aeternae memoriae Illustrissimi et Reverendissimi Domini Hugonis Cavelli (Lovanii, 1627). The biographical data contained in this eulogy, delivered by a former rector of the University of Louvain on the occasion of Mac Cathmhaoil's death, were based on information gleaned from one of his former students, the Franciscan Patrick Fleming (qv), who had intended to write a life of his teacher.