On an April evening over 400 years ago a simple monk faced the emperor of the Holy Roman Empire. His words, heard by only a roomful of people, have echoed through the centuries: My conscience is captive to the Word of God. I cannot and I will not recant any things for to go against conscience is neither right nor safe. Here I stand. Because he took his stand, Martin Luther shattered the structure of medieval Catholicism and initiated Protestantism. This...