Baring-Gould’s sources: Irish Martyrologies. Authority:—The Acts of S. Blaithmac written in verse by his contemporary Walafrid Strabo, and the Irish Annals.

S. Blaithmac was a native of Ireland, son of Flann, perhaps one of the southern Niells, princes of Meath, the names of Flann and Blaithmac having been common in that family. He was heir to a principality, but he abandoned his prospects in this world to become a monk, and afterwards an abbot. Blaithmac had an ardent desire to visit foreign parts, but he was prevented by his friends and companions from leaving Ireland. At length he passed over to Iona, which was shortly after invaded by a party of Northmen. As he was anxious to receive the crown of martyrdom, he determined to remain there whatever might happen, and by his example induced some others to stay with him, advising those who feared death to take refuge on the mainland. While he was celebrating mass the Danes [Viking raiders from Scandinavia] burst into the church, and having slaughtered the monks, demanded of the abbot where was the precious shrine of S. Columba [Irish abbot of Iona (d. 597), apostle of Scotland]. This had been carried off and concealed underground, where the abbot knew not. Accordingly he answered that he was ignorant where it was, and added that even if he had known, he would not have pointed out the spot to them. They then put him to death. The Ulster Annals give his martyrdom in 825-828. The Irish annals generally agree in fixing his death at 823 ( a.d. 824). Mabillon was wrong in supposing it took place in 793. Blaithmac is derived from Blaith, a flower; hence his latinized name is Florigenius or Florus.