After the crucifixion of Christ the Holy Ghost was dealing with Israel to accept Jesus as the Messiah and the Kingdom of God for about a year. But the stoning of Stephen was the final rejection and the unforgivable sin that Jesus spoke of. God put Israel aside for a season. The 12 Apostles mission was cut short and this brought on the mystery program and the Apostle Paul to offer salvation aside from Israel to the Gentiles in this Age of Grace.
Also this video shows why the Roman Catholic pope cannot be a procession that started with Peter.
Times of the Apostles and Dispensational Change