Jerome. Lives of Illustrious Men 29
29 Tatian the heresiarch PL 23, 645
Tatian who, while teaching oratory, won not a little glory in the rhetorical art, was a follower of Justin Martyr and was distinguished so long as he did not leave his master’s side. But afterwards, inflated by a swelling of eloquence, he founded a new heresy which is called that of the Encratites, the heresy which Severus afterwards augmented in such wise that heretics of this party are called Severians to the present day. Tatian wrote besides innumerable volumes, one of which, a most successful book Against the nations, is extant, and this is considered the most significant of all his works. He flourished in the reign of Marcus Antoninus Verus and Lucius Aurelius Commodus.
Tatianus, qui primum Oratoriam docens, non parvam sibi ex arte Rhetorica gloriam comparaverat, Justini martyris sectator fuit, florens in Ecclesia, quamdiu ab ejus latere non discessit. Postea vero inflatus eloquentiae tumore, novam condidit haeresim quae Ἐγκρατιτῶν dicitur, quam postea Severus auxit, a quo ejusdem partis haeretici Severiani usque hodie appellantur. Porro Tatianus infinita scripsit volumina, e quibus unus contra Gentes florentissimus exstat liber, qui inter omnia opera ejus fertur insignis. Et hic sub imperatore M. Antonino Vero, et L. Aurelio Commodo floruit.
Τατιανὸς ὃς πρώην τὴν ῥητορικὴν διδάσκων, οὐκ ἐλαχίστην ἐκ τῆς ῥητορικῆς ἐπιστήμης δόξαν ὠνήσατο, Ἰουστίνου τοῦ μάρτυρος σπουδαστὴς γέγονε διαπρέπων ἐν τῇ ἐκκλησίᾳ, ἐν ὅσῳ τῆς τούτου πλευρᾶς οὐκ ἀπέστη. Ὕστερον δὲ τῷ ὄγκῳ τῆς παιδεύσεως ἐπαρθεὶς, καινὴν συνεστήσατο αἵρεσιν, λέγω δὴ τῶν Ἐγκρατιτῶν, ἣν μετέπειτα Σεβῆρος ἐπηύξησεν, ἀφ' οὗ ἄχρι τοῦ παρόντος οἱ τούτου τοῦ μέρους αἱρετικοὶ Σεβηριανισταὶ ὀνομάζονται. Ὁ δὲ προειρημένος Τατιανὸς πάμπολλα συνεγράψατο τεύχη, ἀφ' ὧν ἐσι κατὰ τῶν ἐθνῶν λόγος εἷς πάνυ θαυμαστὸς, ὃς μεταξὺ πάντων αὐτοῦ τῶν συγγραμμάτων ἐπίσημός ἐστι. Καὶ οὗτος βασιλεύοντος Μάρκου Ἀντωνίνου Βήρου, καὶ Αὐρηλίου Κομόδου ἤνθησεν.