There’s an interesting tidbit where a Catholic Pope speculates about Bishops who would make claim to be the Universal Bishop.
Pope St. Gregory I said:
“
I say it without the least hesitation, whoever calls himself the universal bishop, or desires this title, is, by his pride, the precursor of Antichrist, because he thus attempts to raise himself above the others. The error into which he falls springs from pride equal to that of Antichrist; for as that Wicked One wished to be regarded as exalted above other men, like a god, so likewise whoever would be called sole bishop exalteth himself above others…You know it, my brother; hath not the venerable Council of Chalcedon conferred the honorary title of ‘universal’ upon the bishops of this Apostolic See [Rome], whereof I am, by God’s will, the servant? And yet none of us hath permitted this title to be given to him; none hath assumed this bold title, lest by assuming a special distinction in the dignity of the episcopate, we should seem to refuse it to all the brethren.”
So here you have a pope, speculating on almost parallel lines with Lutheran contentions about the office of the Pope as seen in later years (in Lutheran estimation) - and using the same anti-christ language.
Source:
orthodoxwiki.org/Gregory_the_Dialogist