In my view the opposite approach should be taken. Until I am convinced it's true, it's false.
The fact that the Pope added the Filioque when many past Popes and councils affirmed the Creed without it.
It wasn't the first time something was added to the Creed actually, but the Greeks all of the sudden used this excuse, amongst other things as a red herring for schism.
And the fact that doctrines like Purgatory and Indulgences are solely based on Anselm of Canterbury's Vicarious Atonement theories.
There's much more to it than that, but I don't want to get into a whole discussion about it here.
Along with the fact that Papal Infallibility was dogmatized in the 1870s...
Yes, officially, but was explicitly taught long before that and assumed from the very beginning of the papacy.
Or we can talk about the heresy of Pope Honorius and St. Cyprian's assault against Pope Stephen for calling himself the "Successor of St. Peter" and thinking he was superior to the other Bishops.
Not too familiar with this stuff but again, not pertinent to the discussion here right now. I don't want to get too sidetracked about some Orthodox's percieved "heresies" about past popes. Right now we're on Francis.
Pacwa is wrong that the same people defined Purgatory as those who defined the Trinity. St. Athanasius, and the Cappadocian Fathers along with the entire Church, Eastern and Western defined the Trinity, only a Papal Council decided Purgatory
Pacwa is not wrong, the Greeks were present at Florence Council in 1439 and basically agreed on not only Purgatory but other sticking points like the Filioque and Papal Primacy as well. Unfortunately, with the Fall of Constantinople shortly after, all these agreements fell apart as well.