The reason most of Christendom throughout history believed that is because they were told that by a church that would not give them free access to the Bible. The fact that you would bring up such a weak example of non-rational persuasion shows that you are quite lacking in the evidence department. So far we have 'Luther said' and the bandwagon appeal.
Free access huh? Gee,it’s such a shame that the middle ages didn’t have Obama-mandated free internet for all the illiterates so they could read and study the Bible. I mean it would’ve made it so much easier rather than this hand copy the bible business in the languages of the day and then chain it up in the Church or library so it wouldn’t be stolen.
“The reason most of Christendom throughout history believed that is because they were told that by a church that would not give them free access to the Bible. “
Luther did not have full access to the Bible? How odd.