Papal infallibility was only dogmatised in 1870. However, it had existed for over 800 years before that. Probably in 1075 Pope Hildebrand, Gregory VII, dictated his beliefs about the Papacy, in which he claimed for example that:
The Roman Church was founded solely by God.
Only the Pope can with right be called ‘Universal’.
All princes shall kiss the feet of the Pope alone.
His name alone shall be spoken in the churches.
His title is unique in the world.
It may be permitted to him to depose emperors.
No Council shall be called a Universal Council without his order.
He himself may be judged by no one.
The Roman Church has never erred. Nor will it err, to all eternity – Scripture being witness.
He may depose and reinstate bishops without assembling a Council.
He who is not at peace with the Roman Church shall not be considered ‘Catholic’.
These claims all goes further back, not just to the ‘Reform’ of the 1050s, but, arguably, to the revival of the (pagan) Roman Empire in 800 and that in turn goes back to the absolute power of the pagan Emperor in that Roman Empire. After the pagan emperors in Rome had fallen, the Papacy inherited their infallible authority.
But what happened to all this at the Protestant Reformation?
The Protestants claimed that only the Scriptures are infallible. This, naturally, led to infinite arguments about interpretations, just as in Scholastic Europe. ‘My interpretation is right, yours is wrong’. And so begin new infallibilities. One Protestant disagrees with another and their absolutism leads to a multitude of new ‘churches’ and so to new hatreds in a chain of ‘logic’:
You don’t agree with me. Therefore, I hate you. Therefore, I am going to set up my own Church, where you cannot go because I will not allow you to come in. My moralising is correct because I am superior to you. I will not concelebrate with you because you do not agree with me. Such people with their petty hatreds soon find themselves outside the Church. They claim: ‘He who is against me is an enemy of the Church’. This is because they claim that ‘I am the Church’. It is certainly not Christian, rather a curious mixture of Papism and Stalinism.