Being St. Patrick's day, we should remember Celtic Christianity in all its aesthetic, spiritual and missionary brilliance. It was also tribal, syncretistic and violent but let us remember and celebrate its missionary endevours for the Isles West of the European Continent.
Patrick was not the first to bring Christianity to Ireland, but he is responsible for the majority of the evangelization and establishment of the church there. After Patrick, Christianity continued to flourish in Ireland for the next hundred years and more, with monastic leaders such as Finnian of Clonnard (died AD 549), Finnian of Moville (c. AD 495-579), Brendan of Birr and Brendan of Clonfert (died AD 578) exercising increasing control.
Women were also prominent; Ita of Kileedy (died AD 570) ran a school for boys at her nunnery; Brigit of Kildare (C AD 450-523 or 528) established the first of many "double monasteries", where a monastery and a nunnery existed on the same site.
In Wales, as well as in Strathclyde and Cornwall, the Celtic Church continued to exist. Wales, in particular had a strong line of saintly and scholarly abbots who had great spiritual influence in the churches. Dewi (David c. AD 462-547), Gildas and Cadoc were among the most prominent.
However, no real efforts were made to evangelise the pagan Anglo-Saxons who now dominated the majority of territory in the old Britannia, nor the Picts and Scots in the north of the island.This work of evangelism did not really begin until a hundred years after Patrick's death.
Mission to Scotland began with the journey of Colmcille or Columba to the remote island of Iona in AD 563. Born in AD 521 into the a ruling family, as a young man he entered the monastery of Finnian of Moville, and later joined that of Finnian of Clonnard. Subsequently, he himself founded a number of other monasteries, including that of Derry. He left Ireland in AD 561 "to become an exile for Christ", but a much later document, which modern scholars now accept as giving the full story, speaks of Columba's "soul-friend" and spiritual counsellor Molaise of Devenish imposing on him his departure from Ireland as a penance for a grave sin and its consequences. I.e. he had started a war in which hundreds of people were killed The action was widely condemned, and Columba accepted Molaise's imposition as God's will. He left Ireland determined to atone for his sin by converting as many heathen to Christ as had been killed in the battle.
He and his twelve companions wandered for two years before they settled on the island of Iona in the Inner Hebrides. Here he established a monastery and a college to train young men for the evangelisation of the northern Picts, and from here he and others ventured forth to the mainland as well as to the islands of the Inner and Outer Hebrides. His first visit was to King Brude in Inverness, who was converted as a result. He established friendly relations with Kentigern (or Mungo), bishop of Glasgow, and through him achieved reconciliation between the kings of Argyle and Strathclyde. His biographer Adamnan records many miracles and visions of Columba, as well as widespread success in converting the northern Picts and the Hebridean islanders. He returned to Ireland in 574 for a convention at Drumceatt, and was received with veneration because of his sanctity, miracles and evangelistic success. He died in 597. Other monks, some from Whitehorn, took the gospel to the Outer Hebredes, as well as to the Orkney and Shetland Islands.
Let us give thanks for these Celtic brothers and sisters who brought the transforming gospel of Christ to our islands.