The Pope is the successor of St. Peter; the Catholic bishops are the successors of the Apostles. Collectively, the bishops constitute what is known as the Episcopal College, with the Pope as its head.
Christ made the Apostles as a stable group, or college. They were jointly responsible for spreading the Gospel of Christ in the whole world. To the whole college, Christ addressed His great missionary command, “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you; and lo, I am with you always, to the close of the age” (Matthew 28:19-20).
Jesus said to Peter, “But I have prayed for you that your faith may not fail; and when you have turned again, strengthen your brethren” (Luke 22:32).
When the first council of the Church was held in Jerusalem in the first century, the Apostles, as a college, decided the question whether Jewish customs should be imposed on non-Jewish converts: “For it has seemed good to the Holy Spirit and to us to lay upon you no greater burden than these necessary things: that you abstain from what has been sacrificed to idols and from blood and from what is strangled and from unchastity. If you keep yourselves from these, you will do well. Farewell” (Acts 15:28-29).