CAIUS, POPE, St. — The *Liber Pontificalis* states that he was of Dalmatian origin and even a relative of the emperor Diocletian (though this last detail may be doubted). According to the chronology of the same *Liber Pontificalis*, he was pope from the second consulship of Carus and Carinus (282 or 283) to the sixth of Diocletian and the second of Constantius (295 or 296); he must certainly have governed the Church toward the end of the 3rd century.
His epitaph was discovered in the Catacomb of Callistus (cf. Diehl, *Inscr. Chr.*, no. 961: erroneous transcription); from this inscription it appears that he was “laid to rest” on April 22 (though the day number is not certainly legible). It is also uncertain whether the cubicle where the inscription is found, not “in situ,” is precisely the one that contained the Pope’s remains. The *Epitome Cononiana* and the fuller version of the *Liber Pontificalis* recall an important reform of his by which it was forbidden to ascend to the dignity of bishop without having climbed the ladder of lower grades. What the *Passio s. Susannae* says about C. has no historical value. It is uncertain whether he died a martyr; perhaps he was only a confessor.