As regards rival Isiac and Mithraic baptisms, he asserts that their waters are destitute of divine power; nay, are rather tenanted by the devil who in this matter sets himself to rival God.
About 80 B.C. Sulla founded an Isiac college in Rome, but their altars within the city were overthrown by the consuls no less than four times in the decade from 58 to 48 B.e., and the worship of Isis at Rome continued to be limited or suppressed by a succession of enactments which were enforced until the reign of Caligula.
The Isiac mysteries were a representation of the chief events in the myth of Isis and Osiris - the murder of Osiris, the lamentations of Isis and her wanderings, followed by the triumph of Horus over Seth and the resurrection of the slain god - accompanied by music and an exposition of the inner meaning of the spectacle.