Known to the ancients as Bobium or Ebovium, the Irish Saint Columbanus (It. Colombano) established a monastery sometime between 612 and 614. The monastery became a center of learning during the Middle Ages, and renowned for its library, but declined in the 15th century and the library was dispersed. (This monastery is in part the model for the great monastery in Umberto Eco's novel The Name of the Rose.) The monastery was officially suppressed by the French in 1803.
The bishopric dates from 1014.