A question that has been on my mind is exactly when was the Catholic Church officially established. Some people say that Jesus established it before his crucifixion. Others say that the church was established at Pentecost. Still others bring up that St. Peter did not build his church on the rock in Rome until AD 45, some 12-13 years after the crucifixion.
Even so, nobody knew for sure what to teach.
At first, Christians continued to worship alongside Jewish believers, which historians refer to as Jewish Christianity, but within twenty years of Jesus’s death, Sunday was being regarded as the primary day of worship.[16] As preachers such as Paul of Tarsus began converting Gentiles, Christianity began growing away from Jewish practices[11] to establish itself as a separate religion,[17] though the issue of Paul of Tarsus and Judaism is still debated today. To resolve doctrinal differences among the competing factions within the Church, in or around the year 50, the apostles convened the first Church council, the Council of Jerusalem. This council affirmed that Gentiles could become Christians without adopting all of the Mosaic Law.[18] Growing tensions soon led to a starker separation that was virtually complete by the time Christians refused to join in the Bar Khokba Jewish revolt of 132,[19] however some groups of Christians retained elements of Jewish practice.[20]
The early Christian Church was very loosely organized, resulting in diverse interpretations of Christian beliefs.[21] In part to ensure a greater consistency in their teachings, by the end of the 2nd century Christian communities had evolved a more structured hierarchy, with a central bishop having authority over the clergy in his city,[22] leading to the development of the Metropolitan bishop. The organization of the Church began to mimic that of the Empire; bishops in politically important cities exerted greater authority over bishops in nearby cities.[23] The churches in Antioch, Alexandria, and Rome held the highest positions.[24] Beginning in the 2nd century, bishops often congregated in regional synods to resolve doctrinal and policy issues.[18] Duffy claims that by the 3rd century, the bishop of Rome began to act as a court of appeals for problems that other bishops could not resolve.[25]
Doctrine was further refined by a series of influential theologians and teachers, known collectively as the Church Fathers.[26] From the year 100 onward, proto-orthodox teachers like Ignatius of Antioch and Irenaeus defined Catholic teaching in stark opposition to other things, such as Gnosticism.[27] In the first few centuries of its existence, the Church formed its teachings and traditions into a systematic whole under the influence of theological apologists such as Pope Clement I, Justin Martyr and Augustine of Hippo
Thus when the church first started out, the apostles spread the word but it was not uniform. Then St. Paul began writing his famous epistles that began to change Catholic doctrine. Then when the Council of Jerusalem established the Apostolic Creed, there was more uniformity introduced. By the time Augustine of Hippo came along, the church had changed considerably from its beginnings.
So when can we say that the Catholic Church as we know it today was established?