The Importance of Idolatry in the Church

In pre-reformation times it wasn't like people sat around their kitchen table at night, reading from the King James Bible. Nobody had Bibles. All they knew of the scriptures were what they were taught in church. People believe in all sorts of ridiculous things that weren't Christian whatsoever. Just not ignorance. There's a ton of idolatry out of ignorance at this point too.