The Ladder of Seven Gates a Christian Critic Preserved

The clearest ancient description of what the seven grades meant cosmologically comes not from a Mithraic source but from an opponent of Christianity whose work survives only because a Christian writer quoted it to refute it. Celsus, writing against the new religion in the second century, described a Mithraic diagram of a ladder with seven gates, each gate assigned a metal and a planet, lead for Saturn, tin for Venus, bronze for Jupiter, iron for Mercury, an alloy for Mars, silver for the moon and gold for the sun, through which the initiate's soul was said to climb toward the fixed stars. Origen preserved the passage inside his own rebuttal, Against Celsus, arguing the scheme was borrowed rather than original, and in doing so accidentally kept alive the one substantial ancient account connecting the seven grades documented archaeologically at Ostia and Rome to a stated cosmological purpose. The metals correspond closely to the planetary order the Felicissimus mosaic assigns each grade, which is the closest thing Mithraic studies has to independent confirmation of a written source by a physical one. What the ladder meant experientially, whether initiates understood themselves as literally ascending through the planetary spheres during ritual or read the image more figuratively, Origen's hostile source does not say and no friendly one survives to answer.