4 links
Saint Columban
catholic.org
Long, pious hagiography, but charming in its own way: St. Columban had to leave Ireland because Irish women are so beautiful. By S. Baring-Gould.
St. Columbanus
newadvent.org
Irish-born abbot of Luxeuil and Bobbio, author of a monastic rule and of a penitential, d. 615. Biography in the Catholic Encyclopedia.
The Life of St. Columban
fordham.edu
A seventh-century life of St. Columbanus, by Jonas of Bobbio. Includes the story of the saint's miraculous multiplication of beer. D.C. Munro translation.