Since about the 9th century, Pope, a Latin word for “papa” or “Pappas” in Greek, which means “father”, is the title of the bishop of Rome, the head of the Roman Catholic Church. From the 3rd to the 5th century, it was formerly given, especially to any bishop and sometimes to priests too as an ecclesiastical title expressing affectionate respect.
The Annuario Pontificio, the official directory of the Holy See, describes the office of the Pope by the following titles: Bishop of Rome, Vicar of Jesus Christ, Successor of the Prince of the Apostles, Supreme Pontiff of the Universal Church, Patriarch of the West, Primate of Italy, Metropolitan Archbishop of the Province of Rome, Sovereign of the State of Vatican City, Servant of the Servants of God. The title pope or papa (abbreviated PP.) is officially used only as a less solemn style.
According to the Doctrine of the Catholic church, the Pope is the successor of St. Peter, who was the leader of the Apostles. The Pope, as bishop of Rome, is therefore seen to have full and supreme power of jurisdiction over the universal church in matters of faith and morals, as well as in church discipline and governance. The twofold basis of this doctrine of Papal primacy is the place of St. Peter in the New Testament and the place of the Roman Catholic Church in history. The understanding of papal primacy developed as the church developed, two notable factors being the role of Rome as the imperial city until the 5th century and the religious and political role of the bishop of Rome afterward.
The teaching of the Second Vatican Council (1962–65) on the role of bishops emphasized more on papal prerogatives while maintaining the view that the authority of the bishops as a body cannot be separated from that of the pope as its head.