pope from about 189 to 198/199.

After succeeding St. Eleutherius in 189, Victor tried to assert Roman authority in the early Christian church. Most notably, he tried to sanction the Roman date for Easter over that celebrated by the Quartodecimans of Asia Minor, who kept the holiday on 14 Nisan rather than on the following Sunday. Victor threatened Polycrates (the bishop of Ephesus) and other bishops of Asia Minor with excommunication if they did not abandon their practice, and when they defied him he went through the motions of carrying out the sentence. The sentence was apparently withdrawn later, since the Asian churches remained in communion with Rome, and Quartodeciman practices in fact continued in Asia Minor for several centuries. Still, Victor's threat was reputedly the first papal act to influence the ecclesiastical affairs of the Eastern patriarchs. He is also believed to have been the first pope to have dealings with the imperial household.

Under Victor, Latin replaced Greek as the official language of the Roman church, and Victor himself wrote in Latin. In addition to settling the Easter controversy, he held a number of synods at Rome to deal with the dynamic monarchian heresy of the Byzantine merchant Theodotus, whom Victor excommunicated for teaching that Jesus was a normal human being until his Baptism, when the divine power (dynamis) descended upon him. Victor's actions were more characteristic of a pope than those of preceding bishops of Rome.