St. Patrick's work in Ireland was chiefly concerned with preaching the faith and establishing monasteries which served as centres of education. The great success that attended these efforts earned for Ireland the double title of Island of Saints and a Second Thebaid.
The monastic institutions organized by St. Patrick were characterized from their commencement by an apostolic zeal that knew no bounds. Sufficient scope was not to be found at home, so it was impatient to diffuse itself abroad.
SCOTLAND: Hence in the year 563 St. Columcille, a Donegal native of royal descent, accompanied by twelve companions, crossed the sea in currachs of wickerwork and hides, and sought to land in Caledonia. They reached the desolate Isle of Iona on the day preceding Whitsunday.
Many years before, colonies of Irishmen had settled along the western parts of the present Scotland. The settlement north of the Clyde received the name of the Kingdom of Dalriada. These Dalriadan Irish were Christian at least in name, but their neighbors in the Pictish Highlands were still pagans. Columcille's apostolate was to be among both these peoples. Adamnan says that Columcille came to Caledonia "for the love of Christ's name", and well did his after-life prove the truth of this statement. He had attained his forty-fourth year when King Conall, his kinsman, bestowed Iona upon him and his brethren. The island, situated between the Dalriadans and the Picts of the Highlands, was conveniently placed for missionary work. A numerous community recruited from Ireland, with Columcille as its Abbot, soon caused Iona to become a flourishing centre from which men could go forth to preach Christianity. Monasteries and hermitages rapidly sprang up in the adjacent islands and on the mainland. These, together with the Columban foundations in Ireland, formed one great religious federation, in which the Celtic apostles of the northern races were formed under the influence of the holy founder.
St. Columcille recognized the need of securing permanence for his work by obtaining the conversion of the Pictish rulers, and thus he did not hesitate to approach King Brude in his castle on the banks of the River Ness. St. Comgall and St. Canice were Columcille's companions on his journey through the great glen, now famous for the Caledonian Canal. The royal convert Brude was baptized, and by degrees the people followed the example set them. Opposition, however, was keen and aggressive, and it came from the official representatives of Pictish paganism—the Druids.
Success, too, attended Columcille's ministrations among the Dalriadans, and on the death of their king, Aidan Gabhran, who succeeded to the throne, sought regal consecration from the hands of Columcille. In 597 the saint died, but not before he had won a whole kingdom to Christ and covered the land with churches and monasteries. Today his name is held in honor not by Irishmen alone, but by the Catholics and non-Catholics of the land of his adoption.
There are other saints who either labored in person with Columcille or perpetuated the work he accomplished in Caledonia; and their names add to the glory of Ireland, their birth-land. Thus St. Moluag (592) converted the people of Lismore, and afterwards died at Rosemarkie; St. Drostan, St. Columcille's friend and disciple, established the faith in Aberdeenshire and became abbot of Deer; St. Kieran (548) evangelized Kintyre; St. Mun (635) labored in Argyleshire; St. Buite (521) did the same in Pictland; St. Maelrubha (722) preached in Ross-shire; St. Modan and St. Machar benefited the dwellers on the western and eastern coasts respectively; and St. Fergus in the eighth century became apostle of Forfar, Buchan, and Caithness.
DISTANT ISLANDS: But Irish monks were mariners as well as apostles. Their hide-covered currachs were often launched in the hope of discovering solitudes in the ocean. Adamnan records that Baitan set out with others in search of a desert in the sea. St. Cormac sought a similar retreat and arrived at the Orkneys. St. Molaise's holy isle guards Lamlash Bay, off Arran. The island retreats of the Bass, Inchkeith, May, and Inchcolm, in the Firth of Forth, are associated with the Irish saints Baldred, Adamnan, Adrian, and Columcille. St. Maccaldus, a native of Down, became bishop of the Isle of Man.
Remarkable, too, is the fact that Irish monks sailed by way of the Faroe Islands to distant Iceland. These sailor-clerics, who settled on the southeast of the island, were spoken of by later Norwegians as "papar." After their departure—they were probably driven away by Norwegian pagans—these Icelandic apostles "left behind them Irish books, bells, and croziers, wherefrom one could understand they were Irishmen."
But St. Brendan, the voyager, is the most wonderful of the mariner monks of Ireland. He accomplished apostolic work in both Wales and Scotland, but his seafaring instincts urged him to make missionary voyages to regions hitherto unknown. Some writers, not without reason, have actually maintained that he and his followers traveled as far as the American shore. Be this as it may, the tradition of the discoveries of this Irish monk kept in mind the possibly existing western land, and issued at last in the discovery of the great continent of America by Columbus.