Little is known for certain about the life of the Irish churchman Muirchú (fl. late 7th cent CE). He was present at the Synod of Birr in central Ireland in 697 CE, where he was one of the guarantors of the Cáin Adomnáin (“Law of the Innocents”), suggesting that he was an important member of the Irish Church at that time. His tribe was probably the Túath Mochtaine just south of the ecclesiastical center of Armagh in northeast Ireland, where Muirchú was almost certainly a member of the clergy.

Muirchú was the author of the Vita sancti Patricii, one of …