EUSTATHIUS OF SEBASTE : Bishop of Sebaste (Sebasteia, the capital of Armenia prima the modern Sivas); b. at Sebaste c. 300; d. after 377. He seems to have been the son of Bishop Eulalius of Sebaste. His early theological education was influenced by the teachings of Arius, but he kept aloof from the dogmatic dissensions of time, being attracted entirely by the ascetic ideal. He became presbyter, but on account of his ascetic tendencies fell out with his own father, who excluded him from the communion of prayers (Sozomen, IV., xxiv. 9; Socrates, II., xliii. 1). Some years later he was censured by a synod at Cæsarea probably for the same reason. Eusebius of Constantinople deposed him, but the number of his disciples increased. A synod at Gangra, about 340, investigated the complaints against Eustathius. His disciples were accused of denying salvation to married persons, of favoring their separation from each other, of holding objectionable meetings, of wearing unbecoming garments, of accepting payments in kind which were due to the Church, and of other misdemeanors.. Eustathius himself seems to have been free from eccentricities, and his reputation apparently deterred his opponents from attacking him directly.

Of the next thirteen years nothing is known except that Eustathius became bishop of Sebaste about 356. He is heard of again after the return of Basil to his native country. Basil had also been won for the ascetic ideal, and Eustathius seemed to him the incarnation of monastic virtue. For about a decade and a half, until 372 and 373, they were united by the most intimate friendship and agreed also in doctrine. Eustathius had relinquished his Arianism long before; being averse to all dogmatic extremes, he took the part of the Homoiousians. He was present at the Synod of Ancyra in 358 and was one of the envoys who were sent to the court. The followers of Acacius, however, brought it about that a synod in Melitene, probably in the same year, deposed him from his bishopric, not for dogmatic reasons, but on account of his conduct; there had probably been brought forward complaints like those in Gangra. Meletius of Melitene, later bishop of Antioch, at that time a partizan of Acacius, became his successor. But later Eustathius was one of the Homoiousian deputies who represented the cause of the majority of Seleucia at the court. Like the other deputies he accepted the formula of Nicæa in Constantinople, but he fearlessly expressed his own convictions in the negotiations, and when he was deposed on that account, he did not acknowledge the fact and dared to oppose his enemies in sermons and open letters although the favor of the court was evidently on their side. When under Jovian and in the first period of Valens the Homoiousian party gathered again, Eustathius was one of its most energetic leaders, and when the edict of Valens in 365 again expelled all bishops who had been deposed under Constantius, Eustathius as deputy of several Homoiousian synods went to Rome in 366 and testified to his own and their consent to the Nicene Creed. Nevertheless a rupture took place in 373 between Eustathius and Basil since the latter had become a friend of Meletius of Antioch, the former opponent and rival of Eustathius. There was also a dogmatic difference between them concerning the Holy Spirit. Eustathius considered the Holy Spirit neither created nor divine, but kept aloof from both extremes and became the leader of the Pneumatomachi (see MACEDONIANS AND THE MACEDONIAN SECT) in Asia Minor. He made the impression in large circles of an attractive personality and an efficient preacher, as the leader of the first monks, and as the founder of one of the first hospitals (in Sebaste).

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