“THAT which the Prince of Shepherds and great Shepherd of the sheep, Christ Jesus our Lord, established in the person of the Blessed Apostle Peter to secure the perpetual welfare and lasting good of the Church, must, by the same institution, necessarily abide unceasingly in the Church; which, being founded upon the Rock, will stand firm to the end of the world. For none can doubt—and it is known to all ages—that the Holy and Blessed Peter, the Prince and Chief of the Apostles, the pillar of the faith and foundation of the Catholic Church, received the keys of the kingdom from our Lord Jesus Christ, the Saviour and Redeemer of mankind, and lives, presides, and judges to this day and always, in his successors the Bishops of the Holy See of Rome, which was founded by him, and consecrated by his blood” (Vatican Council, sess. iv. ch. 2; cf. Acts of the Council of Ephesus, sess. ill., Labbe).