Ancient Rome a tolerant place? Pretty much, when it comes to religion, writes Pacific Lutheran University Assistant Professor of Classics Eric Nelson in The Complete Idiot's Guide to the Roman Empire. In fact, there's a strong argument that acceptance of other cultures and religions helped subdue and incorporate into the Empire conquered people throughout the Mediterranean for long periods, in turn helping guarantee Rome's success and longevity. But even as the Romans had no problem with tolerating the gods and religious practices of most of the people they conquered, they did take issue with those of some groups -- such as Christians -- that didn't recognize the authority of the Roman government. They were considered a threat, a view that led to their persecution.
"Christians' personal religious practices contradicted state practice in a manner that could not be solved without one party giving way," writes Nelson. "Neither was very good at that."