Peter Harrison argues in his ‘Religion’ and the Religions in the English Enlightenment (9) that the Reformation contributed massively to the development of a new notion of “religion,” especially in the ways Protestants and Catholics redesigned arguments formerly used against idolatry and paganism to attack the one another. Citing Edward Said, he observes:

“In matters of religion, in the centuries immediately following the Reformation, the exigency which made the most urgent demands in England was to do with the truth of competing Christian factions. Accordingly, the ‘religions’ of the ‘Orient,’ of the Pacific and the Americas, of ancient Greece and Rome were pressed into the service of the religious interests of the West. They became heresies which were formally equivalent to some undesirable version of Christianity, be it papism, Calvinism, Arminianism, or any other of the myriads of Protestant sects.”

Luther especially made use of the medieval Western image of Islam to “show that papism was simply another form of paganism.” Others followed Luther’s lead, criticizing any difference “by virtue of its purported affinity with heathen religion.” This “paganopapism” “eroded the privileged status of the Christian religion, for the continual assertion of fancied parallels between this or that creed of Christianity and types of heathenism led in time to the view that all forms of Christianity had something in common with the other religions. The Christian faith inevitably came to be seen as different only in degree from other creeds.”