quality:correction, structural:expansion, linguistic:voice_change, information:classification
Early Christianity (c. 30–325)

Sources suggest that at first, the terms episcopos and presbyter were used interchangeably, with the consensus among scholars being that by the turn of the 1st and 2nd centuries, local congregations were led by bishops and presbyters, whose duties of office overlapped or were indistinguishable from one another. Some say that there was probably "no single 'monarchical' bishop in Rome before the middle of the 2nd century... and likely later."

In the early Christian era, Rome and a few other cities had claims on the leadership of worldwide Church. James the Just, known as "the brother of the Lord", served as head of the Jerusalem church, which is still honoured as the "Mother Church" in Orthodox tradition. Alexandria had been a center of Jewish learning and became a center of Christian learning. Rome had a large congregation early in the apostolic period whom Paul the Apostle addressed in his Epistle to the Romans, and according to tradition Paul was martyred there.

During the 1st century of the Church (c. 30–130), the Roman capital became recognized as a Christian center of exceptional importance. The church there, at the end of the century, wrote an epistle to the Church in Corinth intervening in a major dispute, and apologizing for not having taken action earlier. There are a few other references of that time to recognition of the authoritative primacy of the Roman See outside of Rome.

In the Ravenna Document of 13 October 2007, theologians chosen by the Catholic and the Eastern Orthodox Churches stated:

Both sides agree that this canonical taxis was recognised by all in the era of the undivided Church. Further, they agree that Rome, as the Church that “presides in love” according to the phrase of St. Ignatius of Antioch (To the Romans, Prologue), occupied the first place in the taxis, and that the bishop of Rome was therefore the protos among the patriarchs. They disagree, however, on the interpretation of the historical evidence from this era regarding the prerogatives of the bishop of Rome as protos, a matter that was already understood in different ways in the first millennium.

In AD 195, Pope Victor I, in what is seen as an exercise of Roman authority over other churches, excommunicated the Quartodecimans for observing Easter on the 14th of Nisan, the date of the Jewish Passover, a tradition handed down by John the Evangelist (see Easter controversy). Celebration of Easter on a Sunday, as insisted on by the pope, is the system that has prevailed (see computus).