As far back asthe 1400s, the Reformers have believed that the Papacy/Pope is the antichrist.
http://www.the-bible-antichrist.com/what-did-reformers-believe.html
This is a list of Reformers and what they had to say about the Papacy. MOre at above link bet here's an example.
Nicolaus Von Amsdorf (1483 - 1565)
"He (the antichrist) will be revealed and come to naught before the last day, so that every man shall comprehend and recognize that the pope is the real, true antichrist and not the vicar of Christ … Therefore those who consider the pope and his bishops as Christian shepherds and bishops are deeply in error, but even more are those who believe the the Turk (ISLAM) is the antichrist. Because the Turk (ISLAM) rules outside of the church and does not sit in the holy place, nor does he seek to bear the name of Christ, but is an open antagonist of Christ and His church. This does not need to be revealed, but it is clear and evident because he persecutes Christians openly and not as the pope does, secretly under the form of Godliness." (Nicolaus Von Amsdorf, Furnemliche und gewisse Zeichen, sig.A2r.,v.)
Martin Luther (1483 - 1546)
"nothing else than the kingdom of Babylon and of very Antichrist. For who is the man of sin and the son of perdition, but he who by his teaching and his ordinances increases the sin and perdition of souls in the church; while he yet sits in the church as if he were God? All these conditions have now for many ages been fulfilled by the papal tyranny." (Martin Luther, First Principles, pp. 196-197)
Flacius (1570)
"The sixth and last reason for our separation from the pope and his followers be this; By many writings of our church, by the Divinely inspired Word, by prophecies concerning the future and by the special characteristics of the Papacy, it has been profusely and thoroughly proved that the pope with his prelates and clergy is the real true great antichrist, that his kingdom is the real Babylon, a never ceasing fountain and a mother of all abominable idolatry." (Flacius, Etliche Hochwichtige Ursachen und Grunde, warum das siche alle Christen von dem Antichrist … absondern sollen)