List of religious populations

There are twelve classical world religions—those religions most often included in history of world religion surveys and studied in world religions classes: Baha’i, Buddhism, Christianity, Confucianism, Hinduism, Islam, Jainism, Judaism, Shinto, Sikhism, Taoism, and Zoroastrianism. Here are overviews of ten of these classical religions.


10. Zoroastrianism – 2.7 million followers

Zoroastrianism is an ancient  religion of Greater Iran. Much like the Roman religion for Rome, it was adopted in differing forms as the generally inclusive overarching state religion of the Achaemenid Empire and subsequent Parthian and Sasanian empires, lending it immense prestige in ancient times. As a result, many aspects of Zoroastrianism, either influenced or were inherited by contemporary and later religious systems, including Second Temple Judaism, Christianity, and Islam. Zoroastrianism was gradually marginalized or otherwise absorbed by Islam from the 7th century onwards with the decline of the Sasanian Empire.