Papal Infallibility and Primacy

If certain persons should be disobedient unto the words spoken by Him through us, let them understand that they will entangle themselves in no slight transgression and danger.

St Clement, Letter to the Corinthians, circa 95

The holy Roman Church has been placed at the forefront not by the conciliar decisions of other churches, but has received the primacy by the evangelic Voice of our Lord and Savior.

St. Damasus I, Decree of Damasus, 382

It is clear that this Church (of Rome) is to all churches throughout the world as the head is to the members, and that whoever separates himself from it becomes an exile from the Christian religion.

St. Boniface 1st, Letter to Rufus, Bishop of Thessaly,
March 11, 422

That which has once been decided by the Apostolic See has never been allowed to be discussed again.

St. Boniface I, Letter to Rufus, Bishop of Thessaly,
March 11, 422

Anyone who dares to secede from Peter's solid rock may understand that he has not part or lot in the Divine Mystery.

St. Leo I, Letter to the Bishops of the Province of Vienne, July 1, 445

The Roman See has never erred, and never will err, because of Christ's promise.

St. Agatho, Letter to the Synod at Constantinople, 680

The pontiffs who have ruled at Rome preside there in order to maintain peace, like a wall joining East and West, occupying the middle ground between them...(the) arbitrators and promoters of peace.

Gregory II, Letter to Emperor Leo II, 727

No one, surely, of sound mind is ignorant that it belongs to our office to reprove any Christian for mortal sin, and if he disregards our censure, to compel him by ecclesiastical censure.

Innocent III, Decretals, c. 1207

Just what do these keys mean, which were entrusted personally to Simon, son of John, to Peter, if they are not an indication of the universal rule over the Church which was entrusted to Him?

John XXIII, Address to the Lenten preachers of Rome,
February 22, 1962