a name given to the Catholics of Antioch in the 4th century, on occasion of their refusal to acknowledge any other bishop beside S. Eustathius, deposed by the Arians.

The denomination was given them during the episcopate of Paulinus, whom the Arians substituted for S. Eustathius, about the year 330, when they began to hold their assemblies apart. About the year 350, Leontius of Phrygia, called 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 they accepting, the church of Antioch served indifferently both the Arians and Catholics.

This, we are told, gave occasion to two institutions, which have subsisted in the church ever since. The first was psalmody in two choirs; though M. Baillet thinks, that if they instituted an alternate psalmody between two choirs, it was between two Catholic choirs, and not by way of response to an Arian choir. The second was the doxology, Glory be to the Father, and the Son, and the Holy Ghost. See Doxology.

This conduct, which seemed to imply a kind of communion with the Arians, gave great offence to abundance of Catholics, who began to hold separate meetings; and thus formed the schism of Antioch. Upon this, the rest, who continued to meet in the church, ceased to be called Eustathians, and that appellation became restrained to the dissenting party. S. Flavianus, bishop of Antioch in 381, and one of his successors, Alexander, in 432, brought to pass a coalition, or reunion, between the Eustathians and the body of the church of Antioch, described with much solemnity by Theodoret, Eccl. i. iii. c. 2.