LINKS Other Britannica Sites Articles from Britannica encyclopedias for elementary and high school students. Christianity - Children's Encyclopedia (Ages 8-11) With some 2 billion followers, Christianity is the world’s most widespread religion. Christianity is based on the life, death, and teachings of Jesus of Nazareth. The religion has three main branches-Roman Catholicism, Eastern Orthodoxy, and Protestantism. Christianity - Student Encyclopedia (Ages 11 and up) The beliefs and practices of Christianity are based on the teachings of Jesus Christ. Christianity is divided into three main denominations: Roman Catholic, Eastern Orthodox, and Protestant. There are more Christians in the world (some 2 billion at the beginning of the 21st century) than followers of any other single religion. (See also Jesus Christ.) The topic Christianity is discussed at the following external Web sites.