Saint Columbanus (540 – 23 November 615; Irish: Columban, meaning the white dove) is an Irish missionary notable for founding a number of monasteries on the European continent from around 590 in the Frankish and Lombard kingdoms, most notably Luxeuil (in present-day France) and Bobbio (Italy), and stands as an exemplar of Irish missionary activity in early medieval Europe.

He spreads among the Franks a Celtic monastic rule and Celtic penitential practices for those repenting of sins, which emphasize private confession to a priest, followed by penances levied by the priest in reparation for the sin.

He is also one of the earliest identifiable Hiberno-Latin writers.