EUSTATHIANS, a name given to the Catholics of Antioch in the fourth century, on occasion of their refusal to acknowledge any other bishop except Eustathius, who had been deposed by the Arians. This denomination was given them during the episcopate of Paulinus, whom the Arians substituted instead of Eustathius, about the year 330, when they began to hold their assemblies apart. About the year 350, Leontius of Phrygia, surnamed the Eunuch, who was an Arian, and was put in the see of Antioch, desired the Eustathians to perform their service in his church; which offer they accepted, and the church of Antioch served indifferently both Arians and Catholics. This, we are told, gave occasion to two institutions, which have ever since subsisted in the church; the first, psalmody in two choirs; and the second, the doxology.
This conduct, which seemed to imply a kind of communion with the Arians, gave great offence to many of the Catholics, who began to hold separate meetings; and hence arose the schism of Antioch. Upon this, the rest, who continued to meet in the church, ceased to be called Eustathians, and that appellation was restricted to the dissenting party. Flavianus, bishop of Antioch, in 381, and one of his successors, Alexander, in 481, brought about a coalition or reunion between the Eustathians and the body of the church of Antioch, which is described with much solemnity by Theodore (Ecclesiast. lib. iii. c. 2).