Its story
Docetism (from the Greek dokein, 'to seem') was not a church or a single school but a tendency found in various 1st- and 2nd-century groups: the idea that the Son of God did not truly take a human body or suffer, but only appeared to. Behind it lay a widespread conviction in the philosophy of the time that matter and suffering are unworthy of the divine.
Several New Testament texts seem to respond to this idea. The First Letter of John says that 'every spirit that confesses that Jesus Christ has come in the flesh is from God' (1 John 4:2), and the Second calls those who do not confess it 'deceivers' (2 John 7). Early in the 2nd century Ignatius of Antioch, on his way to martyrdom, repeats that Christ was 'truly' born of Mary, ate, drank, was crucified and rose, and argues that if he only seemed to suffer, Ignatius' own martyrdom would be meaningless (Trallians 9–10; Smyrnaeans 1–7). Polycarp echoes the formula of 1 John.
Docetic features appear in some Gnostic systems and in Marcion. Around 200, Bishop Serapion of Antioch discouraged use of the Gospel of Peter because he judged it to contain such elements. Irenaeus and Tertullian (On the Flesh of Christ) defended the reality of Christ's body by tying it to salvation: only what is truly assumed can be redeemed, and only a real body can rise.
Although Docetism as such disappeared, the questions it raised—how the divine and the human are united in Christ—lie at the heart of the later Christological debates (Apollinaris, Nestorius, Eutyches). In modern theology 'docetic' is also used broadly for any Christology that weakens Jesus' real humanity.