Saint Cassius of Clermont is venerated as a Christian martyr of the 3rd century.

He was a senator who was converted to Christianity by Austromoine.

[1] Cassius was killed with Victorinus (a pagan priest who had also been converted by Austremonius),[2] Maximus, Anatolius, Linguinus, and others at Clermont-Ferrand by Chrocas, the chieftain of the Alemanni, who were invading Roman Gaul at the time.

[3] Chrocas is said to have killed a total of 6,266 Christians at Clermont at this time, according to tradition.

[4] Gregory of Tours mentions a Church of Saint Cassius the Martyr at Clermont.