The most popular religion in the 1800?

Answer 1

This material contributes to a broad view of the nature of religion and piety in England during the 18th century. The source material evaluates religion before and after the "Glorious Revolution", the Church of England in the period, religious controversies, nonconformity and dissent, popular religion, Roman Catholicism, and religion and politics.
Islam was and continues to be the fastest growing religion in the world.

Answer 2

What country in 1764? In the American colonies most of the population was Christian, though there were some Jews and very likely newly arrived slaves were Muslim. The Native Americans had their own separate religions.

In Europe they were Christian and Jews.

In India the religion was Hindu with some Buddhists and Muslims.

In China they were Buddhists and Confucian.

In Persia they were Muslim, Zoroastrian, Jewish and Christian.

The religion a person had depended on where they were born.