Eustathius of Sebaste
He was originally a monk, and is said to have been the first who made the Armenians acquainted with an ascetic life. For this reason some persons ascribed to him the work on Ascetics, which is usually regarded as the production of Saint Basil of Caesarea.
He must have been a contemporary of Constantine the Great, for Nicephorous states that although he had signed the decrees of the Council of Nicaea, he yet openly sided with the Arians. (Epiphanius Ixxv. 1, etc.; Sozomenus iii. 14; Nicephor. ix. 16.) Eustathius died after 377.