He was, like Patrick, a native of Britain. He was brought to Ireland as a child. His name is British, and Adomnán's Life of Columba describes him as "a certain British stranger, a holy man and a disciple of the holy bishop Patrick". He is said to have founded a monastery in Louth in Ireland. Louth was originally the site of a shrine to the Celtic god Lugh. With twelve companions Saint Mochta founded a large monastery that gained a nation wide reputation. Both monastery and village were burned and plundered frequently by the Danes in the period 829-968.
It is claimed that Mochta lived to be 300 years old - a punishment because he doubted the ages of many of the patriarchs of the Old Testament. Scholars believe that he, the last of Patrick's disciples then alive, died at the age of 90.
The Annals of Ulster report his death twice, in 535 and 537, which points to him being considerably younger than Patrick, whose death the Annals date to 493. The entry for 535 dates his death to the 13th of the Calends of September, i.e. 20 August, and quotes the opening of a letter written by him: "Mauchteus, a sinner, priest, disciple of St Patrick, sends greetings in the Lord." However neither the rest of this letter nor any other compositions of his have survived.
- "St. Mochta", St. Mochta's National School
- "A Gathering of Irish Saints, AOH Division 61, Philadelphia
- Ó Cróinín, Early Medieval Ireland: 400-1200, p. 26-27
- proselytus Brito homo sanctus sancti Patricii episcopi discipulus: Anderson & (eds.), Adomnan's Life of Columba, p. 182 (Second Preface)
- Francis J. Byrne, Irish Kings and High-Kings, Four Courts Press, 2001, p. 162
- Dormitatio Muchti discipuli Patricii .xiii. Kl. Septembris. Sic ipse scripsit in epistola sua: Mauchteus peccator, prespiter, sancti Patrici discipulus, in Domino salutem: Mac Carthy (ed.), Annala Uladh: Annals of Ulster.
- Ó Crónín, "Hiberno-Latin Literature to 1169", in A New History of Ireland vol 1: Prehistoric and Early Ireland, p. 372
- Anderson, Alan O. & Majorie O. Anderson (eds.). Adomnan's Life of Columba. Edinburgh, 1961.
- Ó Crónín, Dáibhí. Early Medieval Ireland: 400-1200. Longman, 1995.
- Ó Crónín, Dáibhí. "Hiberno-Latin Literature to 1169". In Dáibhí Ó Crónín (ed.), A New History of Ireland vol 1: Prehistoric and Early Ireland, Oxford University Press, 2005.
- Mac Carthy, B . (ed.). Annala Uladh: Annals of Ulster. Dublin, 1895, Irish text and English translation