In 1879, Reynolds became the defendant in a landmark legal challenge that inadvertently tested the limits of religious liberty in the United States. The Supreme Court's decision in Reynolds v. United States became the first major interpretation of the First Amendment's Free Exercise Clause, drawing a distinction between religious belief, which is absolutely protected, and religiously motivated conduct, which may be regulated by law.

How did religious reform shape scientific progress? The intriguing link between Protestantism and the Scientific Revolution.

What did the separation of church and state look like during the so-called "dark ages"—the mediaeval period?