Early medieval (6th–7th century)
Feast: November 23
He got kicked out of so many countries that his monasteries ended up scattered across half of Europe.
Columbanus was already middle-aged — past fifty — when he left his Irish monastery at Bangor with twelve companions and crossed into Gaul around 590. The Frankish church he found was tangled up in royal politics, and Columbanus had zero interest in diplomacy. He wrote strict monastic rules that made Benedict's look relaxed: monks who coughed during the psalm got six lashes; showing up late to prayer, the same. His communities at Annegray, Luxeuil, and Fontaine drew hundreds of followers anyway. Then he publicly rebuked Queen Brunhilda for her grandson's illegitimate children. She had him deported. He moved to the shores of Lake Constance and preached to the Alemanni. When that didn't work out either, he crossed the Alps into Lombardy at age seventy and founded Bobbio, the monastery that would become one of medieval Europe's greatest libraries. His letters to popes are startlingly blunt — he once told Boniface IV that people were laughing at Rome's handling of doctrine. He died at Bobbio in 615, having planted monastic roots in what is now France, Switzerland, Austria, Germany, and Italy. The modern Church named him patron of motorcyclists, which honestly fits: he never stopped moving.