Fergno (Fergna, Virgno) Brit (‘the Briton’) (d. 623), 4th abbot of Iona and the first to be described as a bishop in the later martyrologies, was (according to Colgan's (qv) Latin Life) son of Fáilbe, a descendant of Conall Gulban (qv) through his son Énnae Bóguine. He followed his distant relation Colum Cille (qv) to Iona, where he progressed greatly in spirituality. In his ‘Vita Columbae’ (iii, 19), Adomnán (qv) describes him as ‘a young man of good ability’, who, as a young monk, was vouchsafed to see a heavenly light enveloping Colum Cille while he prayed in the chapel on Iona. This was described to Adomnán by Commán, Fergno's nephew, many years later.
Fergno became abbot of Iona in 605 on the death of Laisrén and became the last abbot of Iona who was a member of the community during the lifetime of Colum Cille. During his abbacy, Donnán (qv) and his community on the island of Eigg were murdered by pirates on Easter night, 17 April 615. Fergno's death is registered in the Irish annals and martyrologies, where his feast-day is given as 2 March. Fergno's possible British connections are indicated by his sobriquet. He was succeeded by Ségéne (qv).