Contarini:
There is no evidence that Peter or any other early “Pope” claimed infallibility. Some of the Councils do use language about the See of Rome that amount to a claim of infallibility, but a developed notion of papal infallibility doesn’t appear until the later Middle Ages. That does not of course mean that the doctrine is necessarily false.
Peter did not say anything about infallibility. But, his ex-cathedra preaching was infallible. As for infallibility not appearing until the Middle Ages:
Tertullian 160 AD
Forasmuch, then, as Peter was rebuked because, after he had lived with the Gentiles, he proceeded to separate himself from their company out of respect for persons, the fault surely was one of conversation, not of preaching.
(The Prescription of Heretics, Chapter 23)
Contarini:
Those of us who do not accept this as a matter of faith will not accept this claim wthout evidence. And you will have trouble providing such evidence.
**Sorry, I forgot you were protestant, lol.

**
St. Ambrose 340-397
What else can please them unless(which God forbid) the Godhead of Christ should be denied? Plainly they agree well with the Arian who says that Christ is a creature, which also heathen and Jews most readily acknowledge.
This was decreed at the Synod of Ariminum, and rightly do I detest that council, following the rule of the Nicene Council, from which neither death nor the sword can detach me, which faith the father of your Clemency also. (Letter No. 21)
St. Athanasius 296-373
‘Thus believes the Catholic Church’; and thereupon they confessed how they believed, in order to show their own sentiments were not novel, but Apostolic; and what they wrote down was no discovery of theirs; but is the same as was taught by the Apostles.
(Letter on the Council of Arininum and Seleucia)
**The Acts of the Apostles also shows how councils were needed and are still needed. Ecumenical Councils are infallible when it comes to preaching ofcourse. **
Cantarini:
There’s no evidence that Augustine or Cyprian believed in papal infallibility. On the contrary, both of them were willing to go up against Rome when they thought it was wrong. I don’t dispute that they believed in papal primacy. I believe in it myself.
**Maybe they did not write anything about papal infallibility, but that also doesn’t mean they didn’t believe in it. St. Augustine obviously believed in the infallibility of the Catholic Church and the Ecumenical Councils. He also emphasized on the word “Catholic” and preached that the true church is the one that is known by all as “Catholic.” And papal infallibility was proclaimed in Ecumenical Council. **
Contarini:
Of course papal infallibility existed as a doctrine before Vatican I. One form of it develops in the period of the Christological controversies, in which Rome repeatedly wound up as the champion of orthodoxy (though not always). It appears to have been shelved for centuries as a more administrative and legal conception of the papal office developed. In that rather different context, infallibility appears not to have been affirmed until the 14th century.
**When was Rome not the champion of orthodoxy? Please, back that up. It may have been wrong when it came to secular politics or on how to discipline people. But, when did it ever preach heretical doctrine? Infallibility did not appear in the 14th century only. The apostles themselves were infallible, and because of Peter’s primacy his successors in office too continued that infallibility. **