They say that they did, but it is an outrageous fib. The canon was not formulated or compiled by the Pope, but by the universal agreement of the undivided church. At that time Rome was by no means the leader of all Christians, just of the Italians. In Britain the church was decidedly not Roman, but Celtic, with its own laws and traditions. The churches of Alexandria, Antioch, and Constantinople, if anything, had the pre-eminence at that time!
The universal church of that time did not recognize the Pope as the Vicar of Christ, and refused to allow him this title and authority.
During the Middle Ages Rome refused to allow translations of the Bible into the language of the people, insisting upon the Latin translation known as the Vulgate. In England ordinary people were executed for saying the Lord’s Prayer and Apostle’s Creed in English. When Tyndale translated the Bible into English he was murdered by Rome and its allies, and every copy that the Bishop of London could get his hands on, he burned in huge piles. Papists were Bible-burners, not the benevolent Bible-givers that they now present themselves as.
The truth is that we gave the Bible to the church, who had hidden it away as a book too dangerous to be read. Protestants read it out loud to the people in their own languages in church, over the murderous protests of Rome. Now the Romans are doing it too, and they are following a Protestant tradition in doing so.
We also gave communion to the people, and that weekly. In medieval Romanism the people got it once a year, at Easter, and then only half. To this day they may be denied the wine. Now RCs can have it daily, but only because Protestants blazed the trail.
We also gave congregational worship to the people. In medieval churches the people were silent spectators, watching the priest and his assistants do everything. Protestants included the people’s responses into their liturgies, and gave them Psalms and Canticles to sing. Later what we know as hymns were written, and in time they became a universal practice.
So when you see Roman Catholics responding during the liturgy, taking Communion regularly, and singing in church, know that they are being Protestant!
At least they had the good sense eventually to fall into line, even if it was through gritted teeth, and at the cost of much blood and suffering.
The truth is that Rome refused to read the Bible, it prevented people from doing so, and it murdered those who did.
Our Protestants fathers got hold of copies of the Greek NT from Greek scholars fleeing the fall of Constantinople, translated them into the languages of the people, and put it into their hands, ears, hearts, and minds. Rome did everything in its power to withhold the Bible, but the Reformers would not allow it.