Mac Cathmhaoil was born in 1571 at
Saul, County Down, and received his earliest education in his native place; he trained at one of the
bardic schools still operating in Ulster. He next studied at a famous school in the
Isle of Man. On his return to Ireland, he was hired by
Hugh O'Neill, The O'Neill, 2nd Earl of Tyrone, as a tutor to his sons Henry and Hugh. Mac Cathmhaoil was sent by the Earl as special messenger to the Court of Spain to solicit aid for the Ulster forces. During his stay at
Salamanca, where the Court then resided, he frequented the schools of the university and took doctor's degrees in divinity. Soon afterwards he entered the
Order of Friars Minor. He enjoyed a great reputation as a theologian, and his commentaries on the theologian
Duns Scotus (1266–1308) were held in high repute. It was principally due to his great influence at the Spanish Court that the Irish Franciscan College of
St. Anthony was founded at
Leuven (Louvain). After his admission into the Order, Mac Cathmhaoil taught for some time in the
University of Salamanca. He was appointed as superior and lecturer at
St. Anthony's,
Leuven, and moved to Belgium. Among his pupils were
John Colgan,
Patrick Fleming,
Hugh Ward, and
Antony Hickey. He was summoned to Rome to lecture in the convent of
Aracoeli; but his energies were not limited to his work as professor. He was employed by the pope on several commissions. on 22 September 1626. Mac Cathmhaoil was buried in the Church of St. Isidore. His friend
John O'Neill, 3rd Earl of Tyrone, arranged for a monument to be placed on his grave. The Latin playwright, Nicolaus Vernulæus (1583–1649), delivered a
panegyric before the university commemorating the virtues and learning of the archbishop, saying that he was conspicuous for his virtues, and that his holiness of life and profound learning made him the miracle of his time. This address was later published in
Cologne in 1657. ==Works==