SECULARIZATION. The term secularization came into use in European languages at the Peace of Westphalia in 1648, where it was used to describe the transfer of territories previously under ecclesiastical control to the dominion of lay political authorities. The term secularis was already in use, and the distinction between sacred and secular, roughly equivalent to the differentiation of Christian conceptions of the supernatural from all that was mundane or profane, was widely invoked to assert the superiority of the sacred. Furthermore, the church had long distinguished between those priests called "religious" and those designated as secular priests, that is, between those clergy who functioned within a religious order and those who served the wider society. Later, the term secularization was applied in a different, though related, sense, to the dispensation of priests from their vows. The term was applied in even more diverse ways once the concept acquired a...