they do, and he has merely, on the strength of the general expression that these Gnostics were of the school of Valentinus, boldly assigned to them an early date. Now, as we have stated, he himself admits that Valentinus only came from Egypt to Rome in a.d. 140, and continued teaching till 160,(1) and these dates are most clearly given by Irenæus himself.(2) Why then should Ptolemæus and Heracleon, to take an extreme case, not have known Valentinus in their youth, and yet have flourished chiefly during the last two decades of the second century? Irenæus himself may be cited as a parallel case, which Tischendorf at least cannot gainsay. He is never tired of telling us that Irenæus was the disciple of Polycarp,(3) whose martyrdom he sets about A.D. 165, and he considers that the intercourse of Irenæus with the aged Father must properly be put about a.d. 150,(4) yet he himself dates the death of Irenæus, a.d. 202,(5) and nothing is more certain than that the period of his greatest activity and influence falls precisely in the last twenty years of the second century. Upon his own data, therefore, that Valentinus may have taught for twenty years after his first appearance in Rome in a.d. 140--and there is no ground whatever for asserting that he did not teach for even a much longer period--Ptolemaeus and Heracleon might well have personally sat at the feet of Valentinus in their youth, as Irenseus is said to have done about the very same period at those of Polycarp, and yet, like him, have flourished chiefly towards the end of the century. {219} Although there is not the slightest ground for asserting that Ptolemæus and Heraclcon were not contemporaries with Irenæus, flourishing like him towards the end of the second century, there are, on the other hand, many circumstances which altogether establish, the conclusion that they were. "We have already shown, in treating of Valentinus,(1) that Irenæus principally directs his work against the followers of Valentinus living at the time he wrote, and notably of Ptolemæus and his school.(2) In the preface to the first book, having stated that he writes after personal intercourse with some of the disciples of Valentinus,(3) he more definitely declares his purpose: "We will, then, to the best of our ability, clearly and concisely set forth the opinions of those who are now [------] teaching heresy, _I speak particularly of the disciples of Ptolemæus_ [------] whose system is an offshoot from the school of Valentinus."(4) Nothing could be more explicit. Irenæus in this passage distinctly represents Ptolemæus as teaching at the time he is writing, and this statement alone is decisive, more especially as there is not a single known fact which is either directly or indirectly opposed to it.