St. Columban (540?–615)
Also known as St. Columbanus

Columban had been a monk at the abbey of Bangor when at the age of 45 he was granted leave to go to Europe. He set forth with a dozen companions, and together they founded three monastic centers, including Luxeuil, in the Vosges Mountains of eastern France. But Columban's strict rule and rigid adherence to Irish church customs drew criticism, and he was forced to defend himself in letters to Pope Gregory the Great. In 610, after an impolitic run-in with the local nobility, the Irish-born monks were ordered to return home.

The monks, however, moved south, making their way through Switzerland and over the Alps into Lombardy. Although now at least 70 years old, Columban was again embroiled in an ecclesiastical controversy that also involved Pope Boniface IV. Nevertheless, the monks were given land to establish the great abbey of Bobbio in 614. St. Columban died there the following year.

One of the twelve monks who accompanied St. Columban on his mission was another Irishman, St. Gall (died c. 630), after whom a famous monastery was named in Switzerland.