Patrick, the first missionary of the island, had not been half a century dead when Irish Christianity flung itself with a fiery zeal into battle with the mass of heathenism which was rolling in upon the Christian world.

Irish missionaries laboured among the Picts of the Highlands and among the Frisians of the northern seas.
An Irish missionary, Columban, founded monasteries in Burgundy and the Apennines.

The canton of St.Gall still commemorates in its name another Irish missionary before whom the spirits of flood and fell fled wailing over the waters of the Lake of Constance.

For a time it seemed as if the course of the world's history was to be changed, as if the older Celtic race that Roman and German had swept before them had turned to the moral conquest of their conquerors, as if Celtic and not Latin Christianity was to mould the destinies of the Churches of the West.
[Sidenote: Aidan] On a low island of barren gneiss-rock off the west coast of Scotland an Irish refugee, Columba, had raised the famous mission-station of Iona.

It was within its walls that Oswald in youth found refuge, and on his accession to the throne of Northumbria he called for missionaries from among its monks.