Catechesis: On the Papacy

The pope is not the head of all Christendom “by divine right” or on the basis of God’s Word, because that belongs only to the one who is called Jesus Christ. Instead, the pope is only the bishop, or pastor, of the church at Rome and of those who willingly or through a human institution (that is, through secular authority) have joined themselves to him in order to be Christians alongside him as a brother and companion, but not under him as a lord—as the ancient councils and the time of St. Cyprian demonstrate.—SA II:IV:1

Therefore the church cannot be better ruled and preserved than if we all live under one head, Christ, and all the bishops—equal according to the office (although they may be unequal in their gifts)—keep diligently together in unity of teaching, faith, sacraments, prayers, and works of love, etc.—SA II:IV:9