contact with the school of Ptolemæus and Heracleon, if not with the Gnostic leaders themselves, and shocked as he describes himself as being at the doctrines which they insidiously taught, he undertook, on his return to Lyons, to explain them that others might be exhorted to avoid such an "abyss of madness and blasphemy against Christ."(1) Irenæus gives us other materials for assigning a date to his work. In the third Book he enumerates the bishops who had filled the Episcopal Chair of Rome, and the last whom he names is Eleutherus (a.d. 177--190), who, he says, "now in the twelfth place from the apostles, holds the inheritance of the episcopate."(2) There is, however, another clue which, taken along with this, leads us to a close approximation to the actual date. In the same Book, Irenæus mentions Theodotion's version of the Old Testament: "But not as some of those say," he writes, "who now [------] presume to alter the interpretation of the Scripture: 'Behold the young woman shall conceive, and bring forth a son,' as Theodotion, the Ephesian, translated it, and Aquila of Pontus, both Jewish proselytes."(3) Now we are informed by Epiphanius that Theodotion published his translation during the reign of the Emperor Commodus(4) (a.d. 180--192). The Chronicon Paschale adds that it was during the Consulship of Marcellus, or as Massuet(5) proposes to read Marullus, who, jointly with Ælianus, assumed office a.d. 184. These dates decidedly agree with the passage of Irenæus and with the other data, all of which lead {211} us to about the same period within the episcopate of Eleutherus (+ c. 190).(1) We have here, therefore, a clue to the date at which Irenæus wrote. It must be remembered that at that period the multiplication and dissemination of books was a very slow process. A work published about 184 or 185 could scarcely have come into the possession of Irenæus in Gaul till some years later, and we are, therefore, brought towards the end of the episcopate of Eleutherus as the earliest date at which the first three books of his work against Heresies can well have been written, and the rest must be assigned to a later period under the episcopate of Victor (+ 198--199).(2) At this point we must pause and turn to the evidence which Tischendorf offers regarding the date to be assigned to Heracleon.(3) As in the case of Ptolemæus, we shall give it entire and then examine it in detail. To the all-important question: "How old is Heracleon?" Tischendorf replies: "Irenæus names Heracleon, together 3 Canon Westcott adds no separate testimony. He admits that: "The history of Heracleon, the great Valentinian Commentator, is full of uncertainty. Nothing is known of his country or parentage." On the Canon, p. 263, and in a note: "The exact chronology of the early heretics is very uncertain," p. 264, note 2. p 2 {212}