He was a successor of St. Tigernach in Clones and had for the greater part all the Fourths of the bishop of Oriel and the farming of the priors of Lughbadh and Fermanagh, he was bound for the annates of the rectory in 1477, which was to be united to his canonry for the term of his life. He died on the feast of St. John, Apostle and Evangelist 27 December in 1486,[1] when he is styled coarb, and son of the coarb Séamus mac Ruaidhri Mac Mathghamhna.
^[1] The Annals of Ulster (Author: [unknown]) p. 311
^[2] Annals of the Four Masters note: Rudhraighe mac Ardghail Moir Mheg Mathgamhna tighearna Oirghiall do écc. & a mhac Aedh Ruadh mac Rudhraighe do oirdneadh ina ionad la h-Ua Néill.
^[3] Annals of the Four Masters (Author: [unknown]) note:Philip, son of the Coarb (i.e. James, son of Rury, son of Ardgal) Mac Mahon, a canon chorister at Clogher, Coarb of Clones, Parson of Dartry, &c., died.
^Jstor The Coarb in the Medieval Irish Church. (Circa 1200-1550) by St. John D. Seymour, Proceedings of the Royal Irish Academy, Section C, Vol. 41, (1932 - 1934), pp. 221-222 Published by: Royal Irish Academy