The Adoptionist Christians were one of the major varieties of belief within the Early Church. Unfortunately for the Adoptionists, they were amongst the losing factions of the Church when, in the 4th Century AD, the winning faction (the Paulines) joined up with the Roman Emperors to form the Empire's State Religion. The new Imperial Church then set about 'suppressing' all of its rival factions within Christianity.

The numerous Adoptionist Churches believed that Jesus Christ was purely human, not a god. He was adopted at his baptism by the Biblical God, hence their name 'Adoptionists'. Some Adoptionists believed that the Holy Spirit departed from Jesus at his crucifixion. Other Adoptionists believed it was a different person who was crucified. A third alternative had it that the human Jesus was not dead when taken from the Cross; he was placed in the tomb and helped to escape by his followers.

The Gnostics were another losing faction and the exact opposite, Christologically, of the Adoptionists. The Church Fathers (the apologists for the faction that later became victorious) included the Church of Marcion in their denunciation of the Gnostic Christians. The Marcionites were the first of all Christians to develop a theology, to delineate a canon of sacred texts and to form churches. Indeed, the oldest datable Christian Church is of Marcionite variety, 318 AD Syria. The Marcionites were the main target in the anti-heretical writings of the Church Fathers. In 200 AD Tertullian wrote a five volume book, "Adversus Marcionem". Ironically Tertullian became a heretic himself when he joined the Montanists, one of the Adoptionist Churches.
The Marcionites believed that Jesus Christ was purely divine, that he was not human at all. His apparent humanity was an illusion. A Phantasm, they called it. His Father was the True God, so pure and spiritual that he could have no contact with the material world, nor with humans. The world and humans had been created by the Biblical God, Jehovah, as detailed in the Old Testament. The True God was so horrified and disgusted by Jehovah's behaviour in torturing in eternal hell-fire all the souls of the humans, that the True God sent a part of himself (his son Jesus Christ) to purchase all these souls from their creator, Jehovah, at the price of Christ's degradation, the apparent crucifixion of his Phantasm.

The winning faction's Christology can be seen as the perfect compromise. It was the Pauline position, derived originally from St. Paul. Jesus Christ was human as well as divine! Anyone who thought differently was not a Christian and would reap the consequences. The Emperor Constantine in 325 AD, wielding the might of the Roman Empire, backed this position. Thus finally, in 386 AD, the Emperor Theodosius established the Catholic Orthodox Church as the Religion of the Roman Empire.

The Church of Marcion and the various Gnostic sects were totally suppressed. Their sacred texts met the same fate. The victor's sacred texts later became the New Testament of the Bible. However, the Adoptionist Churches were mainly outside of the Roman Empire, to the East. So they survived the suppression. Some historians claim that it was these heretical Adoptionist Christians who influenced Muhammad. The Holy Spirit had adopted Jesus. Muhammad believed it was his turn next.