EUSTAZIO, bishop of SEBASTE. — Born at the beginning of the 4th century, died after 377. In the dogmatic sphere he was restless, straying into semi-Arianism and later denying the divinity of the Holy Spirit. These errors earned E. admonitions from his friend and later adversary, St Basil the Great. After breaking with him, E. became head of the Macedonians.
E. nevertheless had the merit of introducing into Cappadocia the monastic way of life, seeds which St Basil gathered in order to give them definitive solidity through his work and laws.
BIBL.: S. Salaville, Eustathius, in DThC, V, cols. 1565–71; L. Duchesne, History of the Ancient Church, II, Rome 1911, pp. 227 ff., 288 ff. Ignazio Ortiz de Urbina