The ancient astronomy taught that above the seven planetary spheres was an eighth, the sphere of the fixed stars (Clem. Alex. "Strom". , xxv. p. 636: see also his quotation, , p. 692, of a mention of the fifth heaven in apocryphal writings ascribed to Zephaniah). In the eighth sphere, these Gnostics taught, dwelt the mother to whom all these archons owed their origin, Sophia or Prunikos according to the version of Irenaeus, Barbelo according to that of Epiphanius. In the language of these sects the word hebdomad not only denotes the seven archons, but is also a name of place, denoting the heavenly regions over which the seven archons presided; while Ogdoad denotes the supercelestial regions which lay above their control.