...State why as well? Christianity 2.1 billion Bible Abrahamic Jerusalem Israel , 1st century
Islam 1.4 billion Quran Abrahamic Mecca. Saudi Arabia , around 610
Irreligious/atheism 1.1 billion none N/A none N/A
Hinduism 900 million Vedas Dharmic Varanasi Around 1700–1100 BCE, North India...