Christianity is a monotheistic religion based on the life and teachings of Jesus Christ. It is the world's largest religion, with over 2.4 billion followers, known as Christians. Christians believe that Jesus is the Son of God and the savior of humanity whose coming as the Messiah (the Christ) was prophesied in the Old Testament.
Christian theology is summarized in various creeds. These professions of faith state that Jesus suffered, died, was buried, descended into hell, and rose from the dead, in order to grant eternal life to those who believe in him and trust in him for the remission of their sins. The creeds further maintain that Jesus bodily ascended into heaven, where he reigns with God the Father in the unity of the Holy Spirit, and that he will return to judge the living and the dead and grant eternal life to his followers. His incarnation, earthly ministry, crucifixion, and resurrection are often referred to as "the gospel", meaning "good news". The term gospel also refers to written accounts of Jesus's life and teaching, four of which—Matthew, Mark, Luke, and John—are considered canonical and included in the Christian Bible.
Christianity began as a Second Temple Judaic sect in the mid-1st century. Throughout its history, the religion has weathered schisms and theological disputes that have resulted in many distinct churches and denominations. Worldwide, the three largest branches of Christianity are the Catholic Church, the Eastern Orthodox Church, and the various denominations of Protestantism. The Catholic and Eastern Orthodox churches broke communion with each other in the East-West Schism of 1054; Protestantism came into existence in the Reformation of the 16th century, splitting from the Catholic Church.