This list is Sourced from the Encylopaedia Britannica, Wikipedia, Beliefnet, and Adherents.com (a collection of 43,870 adherent statistics and religious geography citations). The list is based on number of members. For a complete list (which also includes atheism and agnosticism, see the Wikipedia article or the Encylopaedia Britannica chart).
1. Christianity [Abrahamic, 27 AD] 2.1 billion adherents [Wikipedia | Britannica | Beliefnet]
Christianity is a monotheistic religion which is based on the teachings of the Old Testament and Jesus of Nazareth. Christians believe that Jesus, as the Son of God is part of the Trinity (God as three persons in one), the others being God the Father and God the Holy Spirit. Christians believe that Christianity fulfils Judaism. Most Christians believe that the death and resurrection of Jesus to be the cornerstone of their faith. Protestant ofshoots of Christianity believe that salvation comes from the belief in God alone, whereas Catholic and Orthodox Christians belief that faith, combined with good works is required for salvation.



