" For two and a half centuries a long war was waged between the Church and the Roman Empire which began in the age of Nero and never entirely ceased, in spite of occasional periods of truce and relaxation, until the conversion of the Emperor Constantine. The causes of persecution were not immediately obvious, since the Roman Empire was not usually intolerant in religious matters and the Christians were not merely politically inoffensive, but inculcated obedience to the Roman government as a religious duty. "

― Christopher Henry Dawson , The Formation of Christendom