Christianity encompasses an astounding variety of denominations, sects, organizations, and churches. Relationships between these groups range from mutual respect and cooperation to denial that the other group is really "Christian."
At ReligionFacts, we don't take sides — but we do try to categorize and organize information in useful ways.
So we list any religious group that is based primarily on the life or teachings of Jesus Christ under "Christianity." We then organize groups under three broad categories that we hope will help readers understand the general differences between them, as follows.
Early Christian Groups contains minority branches of Christianity that developed in its first few centuries, most of which are no longer practiced today. This includes groups that were declared heresies, such as Pelagianism and Gnosticism, as well as orthodox approaches to Christian theology, like the Alexandrian school.
Mainstream Christianity is a term usually used to refer to the main branches of historical, Trinitarian Christianity: Catholicism, Eastern Orthodoxy, Anglicanism, and Protestantism. Within these broad categories are hundreds of denominations and churches that vary significantly in beliefs and practices. The term "Christian denominations" usually refers to these groups.
New Christian Sects contains groups that were founded in the 19th and 20th centuries and differ significantly in beliefs and practices from Mainstream Christianity, such as Christian Science, the Jehovah's Witnesses, and the Church of Jesus Christ of Latter-Day Saints. These are sometimes classified as New Religious Movements in academic sources.