Jesus appointed the fisherman Simon Peter as the leader of the Twelve Apostles. Peter was his nickname: the Greek word petra means rock. Jesus said he would build his Church on the “rock” that Peter was called to be (Mt. 16:18-19).
Peter and his successors were charged with leading the community of the Church. Peter’s leadership office was always passed on from one pope to the next. This means that our current pope is also a successor of the Apostle Peter.