His cult is attested in the early 5th c. by Prudentius Peristephanon 9, who, traveling from Spain to Rome, tells how he stopped at the Forum Cornelii at the saint’s tomb: on its sides were depicted the events of the martyrdom of Cassian, a teacher of ars notaria who was struck down by his students bearing stilettos the Berna MS, Burgerbibliothek 264, transmits Prudentius’s poem with numerous illustrations. A Carolinian-era Passio s. Cassiani by Ubaldus of Saint-Amand puts Prudentius’s account into prose. Cassian’s mention on 13 August in the Martyrologium hieronymianum attests his cult in the 1st half of the 5th c.; at Milan in 451 there was a votive chapel in his honor; at Rome Pope Symmachus 498–514 dedicated an altar to him in the Vatican basilica. According to a tradition, Peter Chrysologus, the Imolese bishop of Ravenna 424–451, went to Imola to render homage at St. Cassian’s tomb and died there. The tomb became a site of the bishop’s palace and quite famous. The tomb was in use at least from the beginning of the 11th c. until 1132, when the Castrum s. Cassiani was destroyed and the saint’s relics were deposited in the cathedral dedicated to him inside the city. The 12th-c. Vita et gesta Cassiani, Ingenuini et Albini is evidence of St. Cassian’s cult in the Tyrol, at Säben and at Brixen.