Tertullian

“ Where was Marcion then, that shipmaster of Pontus, the zealous student of Stoicism? Where was Valentinus then, the disciple of Platonism? For it is evident that those men lived not so long ago,—in the reign of Antoninus for the most part, [1] —and that they at first were believers in the doctrine of the Catholic Church, in the church of Rome under the episcopate of the blessed Eleutherus, [2] until on account of their ever restless curiosity, with which they even infected the brethren, they were more than once expelled. ”

“ Persons are still living who remember them,—their own actual disciples and successors,—who cannot therefore deny the lateness of their date. But, in fact, by their own works they are convicted, even as the Lord said. [13] For since Marcion separated the New Testament from the Old, he is (necessarily) subsequent to that which he separated, inasmuch as it was only in his power to separate what was (previously) united. Having then been united previous to its separation, the fact of its subsequent separation proves the subsequence also of the man who effected the separation. ”

“ These corrupters of the truth we mention as being more notorious and more public [16] than others. There is, however, a certain man [17] named Nigidius, and Hermogenes, and several others, who still pursue the course [18] of perverting the ways of the Lord. Let them show me by what authority they come! If it be some other God they preach, how comes it that they employ the things and the writings and the names of that God against whom they preach? If it be the same God, why treat Him in some other way? Let them prove themselves to be new apostles! ”