Because of his miracles and ability to cast out demons, in 528, he was urged by the clergy and the people to become bishop.

He converted many and destroyed a temple to the god Pan, and used the materials to build a church.

The altars to Fortunatus and Cassianus of Imola were consecrated by Pope Innocent III in 1198.

Gregory writes, "A certain poor old man was brought to me –because I always love to talk with such men- of whom I inquired his country, and hearing that he was of the city of Todi, I asked him whether he knew Bishop Fortunatus.

The crypt houses a sepulcher containing the remains of Fortunatus and other saints, as well as the tomb of Jacopone da Todi.