Eusebius, in chap. 15, informs us that both Blastus and Florinus drew many away from the church of Rome by their heretical innovations. He does not tell us either there or here the nature of the opinions which Blastus held, but from Pseudo-Tertullian’s Adv. omnes Hær. chap. 8, we learn that Blastus was a Quartodeciman. (“In addition to all these, there is likewise Blastus, who would latently introduce Judaism. For he says the passover is not to be kept otherwise than according to the law of Moses, on the fourteenth of the month.”) From Pacianus’ Epistola ad Sympronian. de catholico nomine, chap. 2, we learn that he was a Montanist; and since the Montanists of Asia Minor were, like the other Christians of that region, Quartodecimans, it is not surprising that Blastus should be at the same time a Montanist and a Quartodeciman. Florinus, as will be shown in the next note, taught his heresies while Victor was bishop of Rome (189–198 or 199); and since Eusebius connects Blastus so closely with him, we may conclude that Blastus flourished at about the same time. Irenæus’ epistle to Blastus, On Schism, is no longer extant. A Syriac fragment of an epistle of Irenæus, addressed to “an Alexandrian,” on the paschal question (Fragment 27 in Harvey’s edition) is possibly a part of this lost epistle. If the one referred to in this fragment be Blastus, he was an Alexandrian, and in that case must have adopted the Quartodeciman position under the influence of the Asiatic Montanists, for the paschal calendar of the Alexandrian church was the same as that of Rome (see the Dict. of Christ. Biog. III. p. 264). If Blastus was a Montanist, as stated by Pacianus, his heresy was quite different from that of Florinus (who was a Gnostic); and the fact that they were leaders of different heresies is confirmed by the words of Eusebius in chap. 15, above: “Each one striving to introduce his own innovations in respect to the truth.” Whether Blastus, like Florinus, was a presbyter, and like him was deposed from his office, we do not know, but the words of Eusebius in chap. 15 seem to favor this supposition.