Who started Docetism?

A:Docetism was a form of early Christian belief that held that Jesus is a mutable figure who represents the archetype of the Self and appears in different ways to initiates with different levels of understanding. The Gospel of Philip says, "Some realise that they are seeing themselves."

We do not know how Docetism started, but it was a Gnostic belief and therefore started among the Gnostic Christians.