Protestantism began in the 16th century.
Most of the movements were intended to overcome the political and worldly power of the Church, with its insistence that its dogma (the teachings it promulgated) was too restrictive, and that too much was going into the Church and not coming out into the society at the time.
So, (forgetting about the eastern schism) there was a reaction against the Pope as the titular head of all Christians. Especially when the Church had gone through a time with two popes, and many popes (and other authorities in the Church) were selling "indulgences" to forgive sin and to pave the way to Heaven for those who were rich.
Remember that many European monarchs owed their thrones to the Church at the time, and were looking for ways to get the Church off their backs so they could wield political power in their own right. The whole system was extremely corrupt, despite some of the priests (including up to the Pope himself) being properly devout. And so the Church (and its "princes") was getting richer and richer (that is controlled the real wealth - the land) while the monarchs themselves were getting poorer and poorer.
Eventually, there was a reaction against the Church, and there were many splits, particularly the Lutherans and the Calvinists, who "protested" against the main powers. Previous protests had been put down harshly, with things like the Inquisition, and the burning (and other tortures) of heretics. But in the 16th century, the number of protesters suddenly reach some kind of critical mass, and that resulted in literally hundreds of sects splitting from the main body of the Church.
So, from a single Church, we had literally hundreds of them, some very local.
Naturally, the protestants were persecuted and hunted as was the usual wont at the time. And there would be "informers" who would lead the authorities, sanctioned by the Church, to capture and enforce the Church dogmas. So, "papists" (those who stuck with the main Church) could not be trusted. (Aside: Think of the U.S. in the late forties and the fifties and their pogroms against communists - same kind of thing: you were either a communist and hence against everything American, or you were an American, against everything that smacked of communism.)
So, Protestant countries started to politically cut out the Church - the Roman Catholics - from everything dealing with politics. It didn't take long for the mistrust of those who professed "the true faith" to become hatred of anything that had to do with catholicism.
Much is made about the King James Version of the Bible and how it is more protestant than the version used by the Catholics - it's a phony argument: most of the people who did the translation for the KJV WERE "papists", and they used the same sources as earlier translations did, which were approved by the Council of Nicea (sometime in the fifth century A.D.)
So, an capsule version of history...