The Marcosians were a Gnostic sect founded by Marcus in Lyon, France, and active in southern Europe from the second to the fourth century.
Women held special status in the Marcosian communities; they were regarded as prophetesses and participated in administering the Eucharistic rites. Irenaeus accused Marcus of seducing his followers and scornfully writes (Adversus Haereses I. 13, 4) that the whole sect was an affair of "silly women".
In many Gnostic belief systems, there exist various emanations of God, who is known by such names as One, Monad, Aion teleos (αἰών τέλεος "The Broadest Aeon"), Bythos (βυθός, "depth" or "profundity"), Arkhe (ἀρχή, "the beginning"). In Gnosticism these emanations of God are named as Proarkhe (προαρχή, "before the beginning") and as Aeons (which are also often named and may be paired or grouped). In different systems these emanations are differently named, classified, and described (but emanation is common to all forms of 'Gnosticism'). In Basilidian Gnosis they are called sonships (υἱότητες huiotetes; sing.: υἱότης huiotes); according to Marcus, they are numbers and sounds; in Valentinianism they form male/female pairs called syzygies (συζυγίαι, from σύζυγοι syzygoi: lit. "yokings together").
This source of all being is an Aeon, in which an inner being dwells, known as Ennoea (ἔννοια, "thought, intent"), Charis (χάρις, "grace") or Sige (σιγή, "silence"). The split perfect being conceives the second Aeon, Nous (Νους, "mind"), within itself. Complex hierarchies of Aeons are thus produced, sometimes to the number of thirty. These Aeons belong to a purely ideal, noumenal, intelligible, or supersensible world; they are immaterial, they are hypostatic ideas. Together with the source from which they emanate, they form Pleroma (πλήρωμα, "fullness"). The lowest regions of Pleroma are closest to darkness; that is, the physical world.
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