The expression, "Dark Ages" reveals that there was a great lack in knowledge of the scriptures, and many Christians throughout Europe were prevented from reading God's Word. It should not be expected of me, I would hope, to produce such material, as the old libraries are filled with the evidences--that families were burned to death at the stake for possessing copies of the Bible.
Let's look at Paul's admonition here:
"A man that is an heretic after the first and second admonition reject" (Titus 3:10)
"If anyone does not love the Lord Jesus Christ, let him be accursed. O Lord, come!" (1 Cor 16:22)
"And if any man obey not our word by this epistle, note that man, and have no company with him, that he may be ashamed. Yet count him not as an enemy, but admonish him as a brother. Now the Lord of peace himself give you peace always by all means. The Lord be with you all." (2 Thess. 3:14-16)
It is interesting to note here Paul's method of dealing with unbelievers. Notice that in Titus 3:10, we are to "reject" heretics. That's it! Nothing more! We are not to place violent hands upon them. God will deal with them. It is not our duty to hurt them. This is why God says
"Vengeance is mine; I will repay, saith the Lord." (Romans 12:19)
In 1 Cor 16:22, notice that Paul says that those who do NOT love God, let them be accursed. Once again, nothing is given concerning any violent action to be taken against them.
In 2 Thess 3:14-16, Paul is very clear---we are not to have company with the one that does not obey the Word. Yet we are not to count him as an "enemy", but admonish him as a "brother". How different the Papacy looked at things during the Middle Ages! It is also too bad that many of the Protestants that separated from Rome continued to carry this trend with them for a while, but eventually they did completely quit killing people for disagreeing.
The question should be asked: Did the Papacy eventually quit persecuting other professed Christians for disagreeing with them because they grew in knowledge of the Bible, and later saw the truth on this matter?
Or did they quit because they lost their Temporal Power over the kings of Europe in the mid 18th century, and now had no choice but to "behave"?
Had the Papacy continued to hold its Temporal Power throughout Europe, would it have continued its persecutions?
I welcome any thoughts on the matter.