Eusebius of Caesarea recounts that a certain Natalius who had at first accepted to be made bishop of a group that held that Christ, though conceived by the Holy Ghost, was a mere man, and even inferior to Melchizedek, then repented and begged Zephyrinus to receive him back into the communion of the Church.
The Roman priest Hippolytus was a vigorous proponent of a Logos doctrine that emphasized the distinction of the Persons of the Trinity. He taught that the Divine Logos that became man in Christ differs in everything from God and is the mediary between God and the world of creatures. This doctrine in the form in which Hippolytus set it forth aroused many doubts, and another theological school appeared in opposition to it, emphasizing the absolute unity of God. This doctrine, known as Monarchianism, affirmed the sole deity of God the Father and considered Christ to be a manifestation of God in the manner (modus) of union with human nature. Consequently they were called Modalists or Patripassians, as according to them it was not the Son of God but the Father who had been crucified. Pope Zephyrinus did not interpose authoritatively in the dispute between the two schools. The heresy of the Modalists was not at first clearly evident, and the doctrine of Hippolytus offered many difficulties as regards the tradition of the Church. Unable to respond adequately to the learned arguments of Hippolytus, Zephyrinus said simply that he acknowledged only one God, and this was the Lord Jesus Christ, but it was the Son, not the Father, who had died.
In his opposition to Zephyrinus, Hippolytus started the first schism in the history of the Christian Church. When Callixtus, whom Hippolytus blamed for the inaction of Zephyrinus, succeeded Zephyrinus as Pope, Hippolytus and a number of his scholars left the Church, and for over ten years Hippolytus stood at the head of a separate congregation, possibly as bishop, and is sometimes considered the first Antipope.