The world's principal religions and spiritual traditions may be classified into a small number of major groups, although this is by no means a uniform practice. This theory began in the 18th century with the goal of recognizing the relative levels of civility in societies. 

 

judasim/islam: In world cultures, there have traditionally been many different groupings of religious belief. In Indian culture, different religious philosophies were traditionally respected as academic differences in pursuit of the same truth. In Islam, the Quran mentions three different categories: Muslims, the People of the Book, and idol worshipers. Initially, Christians had a simple dichotomy of world beliefs: Christian civility versus foreign heresy or barbarity. In the 18th century, heresy was clarified to mean Judaism and Islam

 

christianity/judaism: In 1838, the four-way division of Christianity, Judaism, Mahommedanism  and Paganism was multiplied considerably by Josiah Conder's Analytical and Comparative View of All Religions Now Extant among Mankind. Conder's work still adhered to the four-way classification, but in his eye for detail he puts together much historical work to create something resembling our modern Western image he includes Druze, Yezidis, Mandeans, and Elamites

 

The modern meaning of the phrase "world religion", putting non-Christians at the same level as Christians, began with the 1893 Parliament of the World's Religions in Chicago. The Parliament spurred the creation of a dozen privately funded lectures with the intent of informing people of the diversity of religious experience: these lectures funded researchers such as William James, D. T. Suzuki, and Alan Watts, who greatly influenced the public conception of world religions

 

In the latter half of the 20th century, the category of "world religion" fell into serious question, especially for drawing parallels between vastly different cultures, and thereby creating an arbitrary separation between the religious and the secular. Even history professors have now taken note of these complications and advise against teaching "world religions" in schools.