In Early Christianity Marcionism is the dualist belief system that originates in the teachings of Marcion of Sinope at Rome around the year 144 (115 years and 6 months from the Crucifixion, according to Tertullian's reckoning in Adversus Marcionem, xv).
Marcionism was denounced by its opponents as heresy, and written against, notably by Tertullian, in a five-book treatise Adversus Marcionem, written about 208. However, the strictures against Marcionism predate the authority, claimed by the First Council of Nicaea in 325, to declare what is heretical against the Church. Marcion's writings are lost, though they were widely read and numerous manuscripts must have existed. Even so, many scholars (including Henry Wace) claim it is possible to reconstruct and deduce a large part of ancient Marcionism through what later critics, especially Tertullian, said concerning Marcion.
The movement known as Marcionism began with the teachings and excommunication of Marcion from the Church of Rome around 144. Marcion was reportedly a wealthy shipowner, the son of a bishop of Sinope of Pontus, Asia Minor. He arrived in Rome circa 140, soon after Bar Kokhba's revolt. That revolution, along with other Jewish-Roman wars (the Great Jewish Revolt and the Kitos War), provides some of the historical context of the founding of Marcionism. Marcion was excommunicated from the Roman Church because he was threatening to make schisms in the church (G.R.S. Mead, Fragments of a Faith Forgotten ( London and Benares, 1900; 3rd Edition 1931), pp.241-249).
Marcion used his personal wealth, (particularly a donation returned to him by the Church of Rome after he was excommunicated), to fund an ecclesiastical organization. Marcionism continued in the West for 300 years, although Marcionistic ideas persisted much longer.
The organization continued in the East for some centuries later, particularly outside the Byzantine Empire in areas which later would be dominated by Manichaeism. This is no accident: Mani is believed to have been a Mandaean, and Mandaeanism is related to Marcionism in several ways. For example, both Mandaeanism and Marcionism are characterized by a belief in a Demiurge. The Marcionite organization itself is today extinct, although Mandaeanism is not.
Marcion declared that Christianity was distinct from and in opposition to Judaism. He rejected the entire Hebrew Bible, and declared that the God of the Hebrew Bible was a lesser demiurge, who had created the earth, but was (de facto) the source of evil.
The premise of Marcionism is that many of the teachings of Christ (not Jesus — Marcion treated Jesus as being distinct from Christ) are incompatible with the god of the Jewish religion. Focusing on the Pauline traditions of the Gospel, Marcion felt that all other conceptions of the Gospel, and especially any association with the Old Testament religion, was opposed to, and a backsliding from, the truth. He further regarded the arguments of Paul regarding law and gospel, wrath and grace, works and faith, flesh and spirit, sin and righteousness, death and life, as the essence of religious truth. He ascribed these aspects and characteristics as two principles, the righteous and wrathful god of the Old Testament, who is at the same time identical with the creator of the world, and a second God of the Gospel, quite unknown before Christ, who is only love and mercy. Marcion gathered scriptures from Jewish tradition, and juxtaposed these against the sayings and teachings from Gospel of Luke and the Pauline Epistles (but not the Pastoral Epistles or the Epistle to the Hebrews, and adding the Laodiceans) in a work entitled the Antithesis. Marcion's version of Luke did not resemble the version that is now regarded as canonical. It not only lacked all prophecies of Christ's coming but the differences with the now canonical version had other serious theological implications as well. In bringing together these texts, Marcion redacted what is perhaps the first New Testament canon on record.
Marcionites hold maltheistic views of the god of the Hebrew Bible (mockingly known to them as Yaltabaoth), that he was inconsistent, jealous, wrathful and genocidal, and that the material world he created is defective, a place of suffering; the god who made such a world is a bungling or malicious demiurge. "In the god of the [Old Testament] he saw a being whose character was stern justice, and therefore anger, contentiousness and unmercifulness. The law which rules nature and man appeared to him to accord with the characteristics of this god and the kind of law revealed by him, and therefore it seemed credible to him that this god is the creator and lord of the world (κοσμοκράτωρ). As the law which governs the world is inflexible and yet, on the other hand, full of contradictions, just and again brutal, and as the law of the Old Testament exhibits the same features, so the god of creation was to Marcion a being who united in himself the whole gradations of attributes from justice to malevolence, from obstinacy to inconsistency." In Marcionite belief, Christ is not a Jewish Messiah, but a spiritual entity that was sent by the Monad to reveal the truth about existence, and thus allowing humanity to escape the earthly trap of the demiurge. Marcion called God, the Stranger God, or the Alien God, in some translations, as this deity had not had any previous interactions with the world, and was wholly unknown.
Marcionism is not identical to, but is related to, the various beliefs together called Gnosticism. In various sources, Marcion is often reckoned among the Gnostics, but as the Oxford Dictionary of the Christian Church (3rd ed.) puts it, "it is clear that he would have had little sympathy with their mythological speculations" (p. 1034). In 1911 Henry Wace stated: "A modern divine would turn away from the dreams of Valentinianism in silent contempt; but he could not refuse to discuss the question raised by Marcion, whether there is such opposition between different parts of what he regards as the word of God, that all cannot come from the same author." A primary difference between Marcionites and Gnostics was that the Gnostics based their theology on secret wisdom (as, for example, Valentinius found in the Letters of Paul) of which they claimed to be in possession, whereas Marcion based his theology on the contents of the Letters of Paul and the recorded sayings of Jesus — in other words, an argument from scripture, with Marcion defining what was and was not scripture. The Christology of the Marcionites was primarily Docetic, denying the human nature of Christ. Scholars of early Christianity disagree on whether to classify Marcion as a Gnostic: Adolf Von Harnack does not classify Marcion as a Gnostic, whereas G. R. S. Mead does. Von Harnack argued that Marcion was not a Gnostic in the strict sense because Marcion rejected elaborate creation myths, and did not claim to have special revelation or secret knowledge. Mead claimed Marcionism makes certain points of contact with Gnosticism in its view that the creator of the material world is not the true deity, rejection of materialism and affirmation of a transcedent, purely good spiritual realm in opposition to the evil physical realm, the belief Jesus was sent by the "True" God to save humanity, the central role of Jesus in revealing the requirements of salvation, the belief Paul had a special place in the transmission of this "wisdom", and its docetism. According to the 1911 Encyclopædia Britannica article on Marcion: "It was no mere school for the learned, disclosed no mysteries for the privileged, but sought to lay the foundation of the Christian community on the pure gospel, the authentic institutes of Christ. The pure gospel, however, Marcion found to be everywhere more or less corrupted and mutilated in the Christian circles of his time. His undertaking thus resolved itself into a reformation of Christendom. This reformation was to deliver Christendom from false Jewish doctrines by restoring the Pauline conception of the gospel, —Paul being, according to Marcion, the only apostle who had rightly understood the new message of salvation as delivered by Christ. In Marcion's own view, therefore, the founding of his church—to which he was first driven by opposition—amounts to a reformation of Christendom through a return to the gospel of Christ and to Paul; nothing was to be accepted beyond that. This of itself shows that it is a mistake to reckon Marcion among the Gnostics. A dualist he certainly was, but he was not a Gnostic."
Marcionism shows the influence of Hellenistic philosophy on Christianity, and presents a moral critique of the Old Testament from the standpoint of Platonism. According to Harnack, the sect may have led other Christians to introduce a formal statement of beliefs into their liturgy (see Creed) and to formulate a canon of authoritative Scripture of their own, thus eventually producing the current canon of the New Testament. "As for the main question, however, whether he knew of, or assumes the existence of, a written New Testament of the Church in any sense whatever, in this case an affirmatory answer is most improbable, because if this were so he would have been compelled to make a direct attack upon the New Testament of the Church, and if such an attack had been made we should have heard of it from Tertullian. Marcion, on the contrary, treats the Catholic Church as one that 'follows the Testament of the Creator-God,' and directs the full force of his attack against this Testament and against the falsification of the Gospel and of the Pauline Epistles. His polemic would necessarily have been much less simple if he had been opposed to a Church which, by possessing a New Testament side by side with the Old Testament, had ipso facto placed the latter under the shelter of the former. In fact Marcion’s position towards the Catholic Church is intelligible, in the full force of its simplicity, only under the supposition that the Church had not yet in her hand any 'litera scripta Novi Testamenti.'"
For more informationj about Marcionism see: