Baring-Gould’s sources: Irish Martyrologies. He is not to be confounded with S. Domangart, the brother of S. Domnoch, or Modomnoc (Feb. 13th.) Giraldus Cambrensis calls him Dominick. Usher, thinking this S. Dominick was the same as Dominick of Ossory mentioned elsewhere by Giraldus, and not acquainted with the history of S. Domangart, fell into the mistake of making the mountain Slieve Slainge, called afterwards Slieve Donart, to be Grenore point, in Wexford. Ware followed Usher. Archdall calls the saint S. Domangard of Ossory, whereas the saint of Ossory was Domnoc, or Modomnoc, and not Domangart at all, and makes the promontory Carnsore.

S. Domangart is said to have been the son of Euchodius, king of Ulster, in the latter part of the 5th century, and during a part of the 6th. In the Tripartite Life of S. Patrick [apostle of Ireland (5th century)] he is represented as a bigoted heathen and a persecutor. His two daughters having embraced Christianity made a vow of perpetual virginity, and their father, highly incensed, ordered them to be cast into the sea. Therefore S. Patrick cursed him and his seed for ever, excepting, however, his unborn son, at the petition of the queen, who was with child. The son born to him after this was Domangart, and his birth is placed a short time before the foundation of Armagh, and it is added that he afterwards became a disciple of the apostle. But, as Dr. Lanigan has proved in his "Irish Ecclesiastical History," S. Patrick did not survive the foundation of Armagh more than about ten years. How then could Domangart have been his disciple? Then we are given to understand, that Domangart was not born till after his father's death, which the Four Masters assign to A.D. 503 (504.) This sets aside the whole story; for S. Patrick was dead many years before this date. Jocelin, who follows the Tripartite as to Euchodius, Domangart, &c., omits what is said of the latter having been a disciple of S. Patrick. There is a fable concerning S. Domangart having been raised from the dead at Rome by S. Patrick, according to which he would have lived in the 5th cent. Such contradictory stories show what little reliance can be placed in the accounts of the saint. All that we can be certain of is that he founded a monastery on the promontory of Slieve Slainge, where in Colgan's time stood two churches dedicated to him.