Sources Which Speak of Marcion as Being Early Second Century

[Secret Alias]

There is Clement, Marutha and now Cyril of Alexandria Catech. Lecture 6:

Marcion , that mouthpiece of ungodliness. For he who proclaimed different gods, one the Good, the other the Just, contradicts the Son when He says, O righteous Father. John 17:25 And he who says again that the Father is one, and the maker of the world another, opposes the Son when He says, If then God so clothes the grass of the field which today is, and tomorrow is cast into the furnace of fire Luke 12:28; and, Who makes His sun to rise on the evil and on the good, and sends rain on the just and on the unjust. Matthew 5:45 Here again is a second inventor of more mischief, this Marcion. For being confuted by the testimonies from the Old Testament which are quoted in the New, he was the first who dared to cut those testimonies out , and leave the preaching of the word of faith without witness, thus effacing the true God: and sought to undermine the Church's faith, as if there were no heralds of it.
17. He again was succeeded by another, Basilides, of evil name, and dangerous character, a preacher of impurities. The contest of wickedness was aided also by Valentinus , a preacher of thirty gods.