Saint Patrick (c. 390 – 460) ( , Irish: Naomh Pádraig) was a British-born Christian missionary and is the patron saint of Ireland, along with Brigid of Kildare and Columba. He was educated at a monastery and school of divinity founded by Illtud (at the location of modern Llantwit Major).

When he was about 16 he was captured by Irish raiders and taken as a slave to Ireland, where he lived for six years before escaping and returning to his family. After entering the Church, he later returned to Ireland as a missionary in the north and west of the island, but little is known about the places where he worked and there is no contemporary evidence for any link between Patrick and any known church building.

By the eighth century he had come to be revered as the patron saint of Ireland. The Irish monastery system evolved after the time of Patrick and the Irish church did not develop the diocesan model that Patrick and the other early missionaries had tried to establish.

The available body of evidence does not allow the dates of Patrick's life to be fixed with certainty, but it appears that he was active as a missionary in Ireland during the second half of the fifth century. Two letters from him survive, along with later hagiographies from the seventh century onwards. Many of these works cannot be taken as authentic traditions. Uncritical acceptance of the Annals of Ulster would imply that he lived from 340 to 440, and ministered in what is modern day northern Ireland from 428 onwards.

Saint Patrick's Day (17 March) is celebrated both in and outside of Ireland, as both a liturgical and non-liturgical holiday. Outside of Ireland, it can be a celebration of Ireland itself. In the universal Roman Catholic Church it is an optional memorial, though in the dioceses of Ireland it is a both a solemnity and a holy day of obligation.

Background

Most modern studies of Saint Patrick follow a variant of T. F. O'Rahilly's "Two Patricks" theory. That is to say, many of the traditions later attached to Saint Patrick originally concerned Palladius, a deacon from Gaul who came to Ireland, perhaps sent by Pope Celestine I (died 431). Palladius was not the only early cleric in Ireland at this time. Saints Auxilius, Secundinus and Iserninus are associated with early churches in Munster and Leinster. By this reading, Palladius was active in Ireland until the 460s.

Prosper of Aquitaine's contemporary chronicle states:

Palladius was ordained by Pope Celestine and sent to the Irish believers in Christ as their first bishop.

Prosper associates this with the visits of Germanus of Auxerre to Britain to suppress the Pelagian heresy and it has been suggested that Palladius and his colleagues were sent to Ireland to ensure that exiled Pelagians did not establish themselves among the Irish Christians. The appointment of Palladius and his fellow-bishops was not obviously a mission to convert the Irish, but more probably intended to minister to existing Christian communities in Ireland. The sites of churches associated with Palladius and his colleagues are close to royal centres of the period: Secundus is remembered by Dunshaughlin, County Meath, close to the Hill of Tara which is associated with the High King of Ireland; Killashee, County Kildare, close to Naas with links with the Kings of Leinster, is probably named for Auxilius. This activity was limited to the southern half of Ireland, and there is no evidence for them in Ulster or Connacht.