"Before the Revolutionary War, America was a nation divided by different faiths. But when the war for independence sparked in 1776, colonists united under the banner of religious freedom. Evangelical frontiersmen and Deist intellectuals set aside their differences to defend a belief they shared, the right to worship freely.

"The Civil War was a major turning point in American religious thought, argues Mark A. Noll. Although Christian believers agreed with one another that the Bible was authoritative and that it should be interpreted through commonsense principles, there was rampant disagreement about what Scripture taught about slavery.