Religious Intolerance: As It was in the Beginning...

"While the [sixteenth century European] explorers traveled, their homelands often came ablaze
with the fires of persecution and war. Communities were split apart by ferocious quarrels over theology, first between Catholics and Protestants and later among the scores and even hundreds of different religious groups that began to appear in once-unified Christendom. Amid the storms of ecclesiastical conflict and political struggle that gripped the sixteenth and seventeenth centuries, it is not surprising that concerned believers on all sides grew ever less certain that they alone held God's final truth in their hands. The deadly, destructive wars of religion, which persisted for more than a hundred years in some lands, led people to believe that the truth about religion cannot possibly be found in sects that were prepared to torture and execute opponents, confident their work was God's will."

Daniel L. Pals, Eight Theories of Religion