Philip Schaff

“ By the love of the brotherhood we are bound, and by our apostolic rule we are constrained, to give answer to the inquiries of the brethren, according to what the Lord has given us, and to furnish them with the authority of the seal of the apostles.
Footnotes ↑ Callistus succeeded Zephyrinus in the bishopric of Rome, and discharged the duties of that office for five years. This is all the information which Eusebius (in his Chronicon and Hist. Eccl., vi. 21) gives us in regard to Callistus. Later writers make many other statements. ”