It is important to recognize that separation of the realms of state and church has operated since the beginning of Christianity. It is not an invention of modernity, although in modern times this separation has been given a new and to some degree perverse form. In the Rome of the Caesars, the rulers were the emperors, and the Christian church was a persecuted minority entirely distinct from the empire. Once Christianity became the official religion of the Roman empire in the late fourth century, the two realms were somewhat integrated. But even so, the church administered the sacraments and the emperor ratified and enforced the laws. Even during the tragic time of the Spanish Inquisition, if you committed heresy you were tried by the church, while if you committed murder you were tried by the state. So church and state have functioned as distinct if overlapping jurisdictions throughout Western history. Thus it is today that we in the West stare in horrified incomprehension when an Islamic government proposes to execute awoman for refusing to wear religiously mandated garb or a man for daring to convert to Christianity.
But this sort of thing did happen in the West, and unfortunately its perpetrators were Christians. Starting from the time that Christianity became the official religion of the Roman empire, all the way through the Spanish Inquisition, and even as late as the seventeenth century,
Christian rulers with the support of the churches used the power of the state to enforce religious orthodoxy. Both Catholics and Protestants were guilty of this. The Puritans who fled England for America were not escaping Catholic persecution but Anglican persecution. Their objective in finding a land of their own was not to allow everyone to have religious freedom but rather to impose their version of orthodoxy on the whole society.
