Columbanus
Columbanus (Irish: Columbán, 543 – 21 November 615), also known as St. Columban, was an Irish missionary notable for founding a number of monasteries from around 590 in the Frankish and Lombard kingdoms, most notably Luxeuil Abbey in present-day France and Bobbio Abbey in present-day Italy. He is remembered as a key figure in the Hiberno-Scottish mission, or Irish missionary activity in early medieval Europe.
Columbanus taught a Celtic monastic rule and Celtic penitential practices for those repenting of sins, which emphasised private confession to a priest, followed by penances levied by the priest in reparation for the sins. Columbanus is one of the earliest identifiable Hiberno-Latin writers.
Sources
Most of what we know about Columbanus is based on Columbanus' own works (as far as they have been preserved) and Jonas of Bobbio's Vita Columbani (Life of Columbanus), which was written between 639 and 641. Jonas entered Bobbio after Columbanus' death but relied on reports of monks who still knew Columbanus. A description of miracles of Columbanus written by an anonymous monk of Bobbio is of much later date. In the second volume of his Acta Sanctorum O.S.B., Mabillon gives the life in full, together with an appendix on the miracles of the saint, written by an anonymous member of the Bobbio community.