On the day of Pentecost by Jesus.
That was the Catholic Church with Peter as the Pope.
What was the name of your church again?
So you ignore Peter and the authority that Jesus gave him and his successors? So if you reject Peter, you reject Christ. (Another statement by Jesus)
A heretic of gnostic church?
The first Christians had no doubts about how to determine which was the true Church and which doctrines the true teachings of Christ. The test was simple: Just trace the apostolic succession of the claimants.
Apostolic succession is the line of bishops stretching back to the apostles. All over the world, all Catholic bishops are part of a lineage that goes back to the time of the apostles, something that is impossible in Protestant denominations (most of which do not even claim to have bishops).
The role of apostolic succession in preserving true doctrine is illustrated in the Bible. To make sure that the apostles’ teachings would be passed down after the deaths of the apostles, Paul told Timothy, “[W]hat you have heard from me before many witnesses entrust to faithful men who will be able to teach others also” (2 Tim. 2:2). In this passage he refers to the first three generations of apostolic succession—his own generation, Timothy’s generation, and the generation Timothy will teach.
The Church Fathers, who were links in that chain of succession, regularly appealed to apostolic succession as a test for whether Catholics or heretics had correct doctrine. This was necessary because heretics simply put their own interpretations, even bizarre ones, on Scripture. Clearly, something other than Scripture had to be used as an ultimate test of doctrine in these cases.
Thus the early Church historian J. N. D. Kelly, a Protestant, writes, “[W]here in practice was [the] apostolic testimony or tradition to be found? . . . The most obvious answer was that the apostles had committed it orally to the Church, where it had been handed down from generation to generation. . . . Unlike the alleged secret tradition of the Gnostics, it was entirely public and open, having been entrusted by the apostles to their successors, and by these in turn to those who followed them, and was visible in the Church for all who cared to look for it” (Early Christian Doctrines, 37).