Muirchu

Saint Muirchu (Muirchú moccu Machtheni, in Latin Maccutinus) was a monk and historian from Leinster in Ireland in the seventh century. He is known as the author of the Vita sancti Patricii, the Life of Saint Patrick, one of the first accounts of the fifth-⁠century saint, which credits Patrick with the conversion of Ireland before the spread of monasticism. The work is dedicated to Bishop Aedh of Slébte, who also asked for it and sponsored it. Its value for the fifth century is small, but it shows how Patrick was regarded in the seventh.

Muirchú was perhaps a member of the Tuath Mochtaine clan of the Armagh plain. With Bishop Aedh he is among the clergy recorded as attending the Synod of Birr in 697, which suggests their concern for the unity of the two Churches of Ireland, the southern and the northern, which had differing customs. In the prologue to the Life he says that no one else had attempted such a work except his "father" Cogitosus; scholars understand the word as spiritual father, and Cogitosus is the author of a Life of Saint Brigid from the early seventh century.

The work survives in four manuscripts, all incomplete; the most important is the Book of Armagh, copied in 807. Muirchú is commemorated on 8 June as a saint of the West before the Great Schism (a saint of the undivided Church), by the New Calendar.