A Christian is someone who adheres to Christianity, an Abrahamic, monotheistic, religion based on the life and teachings of Jesus of Nazareth. Christians believe that he was the Messiah (the Christ in Greek) prophesied in the Old Testament/Hebrew Bible, and the Son of God. Most Christians believe in the doctrine of the Trinity ("tri-unity"), a description of God as Father, as Son and as Holy Spirit. This includes Roman Catholicism, Orthodox Christianity and the vast majority of Protestantism.
