It was only the European exhaustion over the many violent wars of the Reformation era, and the subsequent secular rationalism of the Enlightenment, that led to a political solution that honored individual liberty in matters of religion.
This story, however, is not only superficial and inadequate, but backward. Religious historian Robert Louis Wilken’s Liberty in the Things of God documents how the origins of religious freedom aren’t secular, but decidedly Christian.
Tertullian, a North African Christian writer of the early third century, was the first to argue that because religious faith is an inward disposition of the mind and heart, it cannot be coerced by external forces. The Church Father writes:
It is only just and a privilege inherent in human nature that every person should be able to worship according to his own convictions; the religious practice of one person neither harms nor helps another. It is not part of religion to coerce religious practice, for it is by choice not coercion that we should be led to religion.CASEY CHALK