(Θεμίστιος).
1. The distinguished philosopher and rhetorician, surnamed Euphrades on account of his eloquence, was a Paphlagonian, the son of Eugenius, who was also a distinguished philosopher, and who is more than once mentioned in the orations of Themistius. He flourished, first at Constantinople and afterwards at Rome, in the reigns of Constantius, Julian, Jovian, Valens, Gratian, and Theodosius; and he enjoyed the favour of all those emperors, notwithstanding their diversities of character and opinion, and notwithstanding the fact that he himself was not a Christian. Themistius was instructed by his father in philosophy, and devoted himself chiefly to Aristotle, though he also studied the systems of Pythagoras and Plato. While still a youth he wrote commentaries on Aristotle, which were made public without his consent, and obtained for him a high reputation. He passed his youth in Asia Minor and Syria. He first met with Constantius when the emperor visited Aneyra in Galatia in the eleventh year of his reign, B. C. 347, on which occasion Themistius delivered the first of his extant orations, περὶ φιλανθρωπίας. It was not long after that he fixed his residence at Constantinople, where he taught philosophy for twenty years. In A. D. 355 he was made a senator; amid the letter is still extant, in which Constantius recommends him to the senate, and speaks in the highest terms both of Themistius himself and of his father. We also possess the oration of thanks which Themistius addressed to the senate of Constantinople early in A.D. 356, in reply to the emperor's letter (Orat. ii.). In A. D. 357 he recited in the senate of Constantinople two orations in honour of Constantius, which were intended to have been delivered before the emperor himself, who was then at Rome (Orat. iii. iv.). As the reward of his panegyrics, Constantius conferred upon him the honour of a bronze statue ; and, in A. D. 361, he was appointed to the praetorian dignity by a decree still extant, in which he is mentioned in the following terms, Themistius, cujus auget scientia dignitatem (Cod. Theodos. vi. tit. 4. s. 12; comp. Orat. xxxi., in which Themistius says, ἀρκεῖ μοι Κωνστάντιος, ὁ κόσμον τῆς ἑαυτοῦ βασιλείας τὴν ἐμὴν φιλοσοφίαν εἰπὼν πολλάκις, and in which he also recites the compliments paid to him by Julian, Valens, Gratian, and Theodosius). Constantius died in A. D. 361 ; but Themistius, as a philosopher and a heathen, naturally retained the favour of Julian, who spoke of him as the worthy senator of the whole world, and as the first philosopher of his age. (Themist. Orat. xxxi.) Suidas (s. v.) states that Julian made Themistius prefect of Constantinople; but this is disproved by the speech delivered by Themistius, when he was really appointed to that office under Theodosius. (See below ) The error of Suidas
In A. D. 377 we find him at Rome, whither he appears to have gone on an embassy to Gratian, to whom he there delivered his oration entitled Ἐρωτικός (Orat. xiii.). On the association of Theodosius in the empire by Gratian, at Sirmium, in A. D. 379, Themistius delivered an elegant oration, congratulating the new emperor on his elevation (Orat. xiv.). Of his remaining orations some are public and some private; but few of them demand special notice as connected with the events of his life. In A. D. 384, about the first of September, he was made prefect of Constantinople (Orat. xvii.), an office which had been offered to him, but declined, several times before (Orat. 34.13). He only held the prefecture a few months, as we learn from an oration delivered after he had laid down the office (Oral. xxxiv.), in which he mentions, as he had done even six years earlier (Orat. xiv.), and more than once in the interval (Or. xv. xvi.), his old age and ill-health. From the 34th oration we also learn that he had previously held the offices of princeps senatus and pracfectus annonae, besides his embassy to Rome; in another oration he mentions ten embassies on which he had been sent before his prefecture (Orat. xvii.); and in another, composed probably about A. D. 387, he says that he has been engaged for nearly forty years in public business and in embassies (Orat. xxi.). So great was the confidence reposed in him by Theodosius, that, though Themistius was a heathen, the emperor, when departing for the West to oppose Maximus, entrusted his son Arcadius to the tutorship of the philosopher, A. D. 387-388. (Socrat. H. E. 4.32; Sozom. H. E. 6.36; Niceph. H. E. 11.46.) We have no particulars of the history of Themistius after this time; and it may therefore be inferred that his life did not extend much, if at all, beyond A. D. 390. Besides the emperors, to whom so many references have been made, he numbered among his friends the chief orators and philosophers of the age, Christian as well as heathen. Not only Libanius, but Gregory of Nazianzus also was his friend and correspondent, and the latter, in an epistle still extant, calls him the " king of arguments" (βασιλέα λόγων, Greg. Naz. Epist. 140).