The Marcosians were a Gnostic sect founded by Marcus, active in Lyon, France and southern Europe from the second to the 4th century. Women held special status in the Marcosian communities; they were regarded as prophetesses and participated in administering the Eucharistic rites. Irenaeus accuses Marcus of seducing his followers, and scornfully writes (Adversus Haereses I. 13, 4) that the whole sect was an affair of "silly women."
The Marcosian system was a variation of that of Valentinus. It retained the 30 Aeons, but called them "Greatnesses" and gave them numerical values. It kept the myth of the fall of Sophia but called it a "Divine Deficiency". Unique to it was the adaptation of the Pythagorean number theory (Isopsephy) to Gnosticism.
Marcus holds his knowledge to be the product of a divine revelation of the body of the Anthropos:
The infinitely exalted Tetrad descended upon him from the invisible and indescribable places in the form of a woman . . . and expounded to him alone its own nature, and the origin of all things, which it had never before revealed to any one either of gods or men. . . . [and] said:—I wish to show thee Aletheia (Truth) herself; for I have brought her down from the dwellings above, that thou mayest see her without a veil, and understand her beauty—that thou mayest also hear her speaking, and admire her wisdom. Behold, then, her head on high, Alpha and Omega; her neck, Beta and Psi; her shoulders with her hands, Gamma and Chi; her breast, Delta and Phi; her diaphragm, Epsilon and Upsilon; her back, Zeta and Tau; her belly, Eta and Sigma; her thighs, Theta and Rho; her knees, Iota and Pi; her legs, Kappa and Omicron; her ankles, Lambda and Xi; her feet, Mu and Nu. Such is the body of Truth, according to this magician, such the figure of the element, such the character of the letter. And he calls this element Anthropos (Man), and says that is the fountain of all speech, and the beginning of all sound, and the expression of all that is unspeakable, and the mouth of the silent Sige.