The Bible does contain many truths, but during the Middle Ages, to which @lynncoyle1 spoke to, it wasn't readily available to the people. That didn't start to happen until the period of the Reformation, which came after. So, the Church did have primary control over the interpretation of the Bible and, at least according to the reformers, not all of what they taught was biblically based.

So, I would say you could debate either side of the control issue, whether it was actually good or not and probably have a fairly long list on both sides. I believe some pretty good people went to their deaths as heretics because they dared to interpret the teachings in the Bible differently than the prevailing doctrine of the Church.