Eustathius semi-Arian bishop of Sebaste, in Armenia, in the fourth century, was a great advocate of monasticism, which he introduced into Armenia. The ascetic fanatics called Eustathians are supposed to have taken their name and their practices from him (but SEE EUSTATHIANS, 2). He also founded in Sebaste a hospital for the poor, over which he placed Aarius, then his devoted friend. But later Aarius charged him with avarice, and they quarreled. SEE LERIANS. Eustathius died about A.D. 380. — Socrates Hist. Eccl. 2:43; Sozomen, Hist. Eccl. 3:14; Neander, Church Hist. Torrey's transl. 2:342; Hefele, Concliengaeschichtea 1:652 sq.