Marcus (17) a Gnostic of the school of Valentinus who taught in the middle of the 2nd cent. His doctrines are almost exclusively known to us through a long section (i. 13–21 pp. 55–98) in which Irenaeus gives an account of his teaching and his school. Both Hippolytus (Ref. vi. 39–55 pp. 200–220 and Epiphanius (Haer. 34) have copied the account from Irenaeus; and there seems no good reason to think that either had any direct knowledge of the writings of Marcus. But Clement of Alexandria clearly knew and used them. Although Jerome describes Marcus as a Basilidian (Ep. 75 ad Theod. i. 449) what Irenaeus reports clearly shews him as a follower of Valentinus. Thus his system tells of 30 Aeons divided into an Ogdoad a Decad and a Dodecad; of the fall and recovery of Sophia; of the future union of the spirits of the chosen seed with angels as their heavenly bridegrooms. What Marcus added to the teaching of his predecessors is perhaps the most worthless of all that passed under the name of "knowledge" in the 2nd cent. It merely contains magical formulae which the disciples were to get by heart and put trust in and puerile speculations such as were in vogue among the later Pythagoreans about mysteries in numbers and names. Marcus found in Scripture and in Nature repeated examples of the occurrence of his mystical numbers four six eight ten twelve thirty. If so great mysteries were contained in names it naturally followed that to know the right name of each celestial power was a matter of vital importance; and such knowledge the heretical teachers promised to bestow. They had formulae and sacraments of redemption. They taught that the baptism of the visible Jesus was but for the forgiveness of sins but that the redemption of Him Who in that baptism descended was for perfection; the one was merely psychical the other spiritual. Of the latter are interpreted the words in which our Lord spoke of another baptism (Luk_12:50
). Some conferred this redemption by baptism with special invocations; others added or substituted various anointings; others held that these applications could not procure spiritual redemption—only by knowledge could such redemption be effected. This knowledge included the possession of formulae by the use of which the initiated would after death become incomprehensible and invisible to principalities and powers and leaving their bodies in this lower creation and their souls with the Demiurge ascend in their spirits to the Pleroma. Probably the Egyptian religion contributed this element to Gnosticism. Some of these Marcosian formulae were in Hebrew of which Irenaeus has preserved specimens much corrupted by copyists. Marcus as Irenaeus tells us used other juggling tricks by which he gained the reputation of magical skill. A knowledge of astrology was among his accomplishments and apparently some chemical knowledge with which he astonished and impressed his disciples. The eucharistic cup of mingled wine and water was seen under his invocation to change to a purple red; and his disciples were told that this was because the great CHARIS had dropped some of her blood into the cup. Sometimes he would hand the cup to women and bid them in his presence pronounce the eucharistic words; and then he would pour from their consecrated cup into a much larger one held by himself and the liquor miraculously increased at his prayer would be seen to rise up and fill the larger vessel. He taught his female disciples to prophesy. Casting lots at their meetings he would command her on whom the lot fell boldly to utter the words which were suggested to her mind and such words were accepted by the hearers as prophetic utterances. He abused the influence he thus acquired over silly women to draw much money from them and it is said even to gain from them more shameful compliances. He is accused of having used philtres and love charms and at least one if not more of his female disciples on returning to the church confessed that body as well as mind had been defiled by him. Some of his followers certainly claimed to have been elevated by their knowledge and the redemption they had experienced above ordinary rules of morality. If we are sometimes tempted to be indulgent to Gnostic theories as the harmless dreams of well-meaning thinkers perplexed by problems too hard for them the history of Marcus shews how these speculations became a degrading superstition. Everything elevating and ennobling in Christ's teaching disappeared; the teachers boasted of a sham science having no tendency to make those who believed it wiser or better; the disciples trusted in magical rites and charms not more respectable than those of the heathen; and their morality became of quite heathen laxity.
Marcus appears to have been an elder contemporary of Irenaeus, who speaks of him as though still living and teaching. Irenaeus more than once tells of the resistance to Marcus of a venerated elder, from whom he quotes some iambic verses, written in reprobation of that heretic. Though we learn from Irenaeus that the Rhone district was much infested by followers of Marcus, it does not appear that Marcus was there himself, and the impression left is that Irenaeus knew the followers of Marcus by personal intercourse, Marcus only by his writings. We are told also of Marcus having seduced the wife of one of the deacons in Asia (διάκονον τινα τῶν ἐν τῇ Ἀσίᾳ ) and the most natural conclusion is that Asia Minor was the scene where Marcus made himself notorious as a teacher, probably before Irenaeus had left that district; that it was a leading bishop there who resisted Marcus; and that the heretic's doctrines passed into Gaul by means of the extensive intercourse well known to have then prevailed between the two countries. The use of Hebrew or Syriac names in the Marcosian school may lead us to ascribe to Marcus an Oriental origin.