Charles Buck Theological Dictionary 
Or MARCIONISTS, Marconistae, a very ancient and popular sect of heretics, who, in the time of Epiphanius, were spread over Italy, Egypt, Palestine, Syria, Arabia, Persia, and other countries: they were thus denominated from their author Marcion. Marcion was of Pontus, the son of a bishop, and at first made profession of the monastical life; but he was excommunicated by his own father, who would never admit him again into communion with the church, not even on his repentance. On this he abandoned his own country, and retired to Rome, where he began to broach his doctrines. He laid down two principles, the one good, the other evil; between these he imagined an intermediate kind of Deity, of a mixed nature, who was the Creator of this inferior world, and the god and legislator of the Jewish nation: the other nations who worshipped a variety of gods, were supposed to be under the empire of the evil principle. These two conflicting powers exercised oppressions upon rational and immortal souls; and therefore the supreme God, to deliver them from bondage, sent to the Jews a Being more like unto himself, even his Son Jesus Christ, clothed with a certain shadowy resemblance of a body: this celestial messenger was attacked by the prince of darkness, and by the god of the Jews, but without effect.
Those who followed the directions of this celestial conductor, mortify the body by fastings and austerities, and renounce the precepts of the god of the Jews and of the prince of darkness, shall after death ascend to the mansions of felicity and perfection. The rule of manners which Marcion prescribed to his followers was excessively austere, containing an express prohibition of wedlock, wine, flesh, and all the external comforts of life. Marcion denied the real birth, incarnation, and passion of Jesus Christ, and held them to be apparent only. He denied the resurrection of the body, and allowed none to be baptized but those who preserved their continence; but these he granted might be baptized three times. In many things he followed the sentiments of the heretic Cerdon, and rejected the law and the prophets. He pretended the Gospel had been corrupted by false prophets, and allowed none of the evangelists but St. Luke, whom also he altered in many places, as well as the epistles of St. Paul, a great many things in which he threw out. In his own copy of St. Luke he threw out the first two chapters entire.
Heresies of the Church Thru the Ages 
Born c110 Founder, in Rome in 144, of a sect called the Marcionites. Amazed at what he considered the opposition between the Old and New Dispensations, Marcion rejected the former and declared the Apostles had been in error in linking the New Covenant with the Old. He claimed to be interpreting true Christianity as taught by Saint Paul. He prepared a mutilated edition of the New Testament (consisting of a large part of the Gospel of Saint Luke and ten Epistles of Saint Paul) and organized his church along hierarchical lines. It is difficult to distinguish some of the doctrines he held from those of the Gnostics, with which his followers were almost immediately identified, but he certainly taught that the God of the Jews was a Demiurge and that Christ had come among men to tell them about the true God, His Father. Married persons could never rise above the catechumenate in his sect, in which the baptized were virgins, widows, celibates, and eunuchs. The Marcionites ceased to flourish in the 7th century.