Ten saints of this name are mentioned in the martyrology of Donegal. The exact date and place of Fergus's birth remain unknown. He was a contemporary of St.
Drostan and St.
Donevaldus. Known in the Irish martyrologies as St. Fergus Cruithneach, or the Pict, the Breviary of Aberdeen states that he had been a bishop for many years in Ireland when he went on a mission to Alba with some chosen priests and other clerics. He settled first near
Strageath, in Upper Strathearn, in Upper Perth, and erected three churches in that district. The churches of Strageath, Blackford, and Dolpatrick are found there dedicated to St. Patrick. He next evangelized Caithness and established there the churches of Wick and Halkirk. ==Veneration==