A name frequently given to the conservative majority in the East in the fourth century as opposed to the strict Arians. More accurately it is reserved (as by St. Epiphanius, "Hær" lxxiii) for the party of reaction headed by Basil of Ancyra in 358. The greater number of the Eastern bishops, who agreed to the deposition of St. Athanasius at Tyre in 335 and received the Arians to communion at Jerusalem on their repentance, were not Arians, yet they were far from being all orthodox. The dedication Council of Antioch in 341 put forth a creed which was unexceptionable but for its omission of the Nicene "of One Substance". Even disciples of Anius, such as George, Bishop of Laodicea (335-47) and Eustathius of Sebaste (c. 356-80), joined the moderate party, and after the death of Eusebius of Nicomedia, the leaders of the count faction, Ursacius, Valens, and Germinius, were not tied to any formula, for Constantius himself hated Arianism, though he disliked Athanasius yet more. When Marcellus of Ancyra was deposed in 336, he was succeeded by Basil. Marcellus was reinstated by the Council of Sardica and the pope in 343, but Basil was restored in 350 by Constantius, over whom he gained considerable influence. He was the leader of a council at Sirmium in 351 held against Photinus who had been a deacon at Ancyra, and the canons of this synod begin by condemning Arianism though they do not quite come up to the Nicene standard. Basil had afterwards a disputation with the Arian Aëtius. After the defeat of Magnentius at Mursa in 351, Valens, bishop of that city, became the spiritual director of Constantius. In 355 Valens and Ursacius obtained the exile of the Western confessors Eusebius, Lucifer, Liberius, and that of Hilary followed. In 357 they issued the second Creed of Sirmium, or "formula of Hosius", in which homoousios and homoiousios were both rejected. Eudoxius, a violent Arian, seized the See of Antioch, and supported Aëtius and his disciple Eunomius.

In the Lent of 358 Basil with many bishops was holding the dedicatory feast of a new church he had built at Ancyra, when he received a letter from George of Laodicea relating how Eudoxius had approved of Aëtius, and begging Macedonius of Constantinople, Basil, and the rest of the assembled bishops to decree the expulsion of Eudoxius and his followers from Antioch, else that great see were lost. In consequence the Synod of Ancyra published a long reply addressed to George and the other bishops of Phoenicia, in which they recite the Creed of Antioch (341), adding explanations against the "unlikeness" of the Son to the Father taught by the Arians (Anomoeans, from anomoios), and showing that the very name of father implies a son of like substance ( homoiousios, or homoios kat ousian) Anathematisms are appended in which Anomoeanism is explicitly condemned and the teaching of "likeness of substance" enforced. The nineteenth of these canons forbids the use also of homoousios and tautoousios; this may be an afterthought due to the instance of Macedonius, as Basil does not seem to have insisted on it later. Legates were dispatched to the Count at Sirmium-, Eustathius of Sebaste, an ascetic of no dogmatic principles, Eleusius of Cyzicus, a follower of Macedonius, and Leontius, a priest who was one of the emperor's chaplains. They arrived just in time, for the emperor had been lending his ear to an Eudoxian; but he now veered round, and issued a letter (Sozomen, IV, xiv) declaring the Son to be "like in substance" to the Father, and condemning the Arians of Antioch.

According to Sozomen it was at this point that Libenius was released from exile on his signing three fornmulæ combined by Basil; against this story see LIBERIUS, POPE. Basil persuaded Constantius to summon a general council, Ancyra being proposed then Nicomedia; but the latter city was destroyed by an earthquake; Basil, therefore, was again at Sirmium in 359 where the Arianizers had meanwhile regained their footing With Germinius of Sirmium, George of Alexandria, Ursacius and Valens, and Marcus of Arethusa, he held a conference which lasted until night. A confession of faith, ridiculed under the name of the "dated creed", was drawn up by Marcus on 22 May (Hilary, "Fragment. xv"). Arianism was of course rejected, but the homoios kata ten ousian was not admitted, and the expression kata panta homoios, "like in all things", was substituted. Basil was disappointed, and added to his signature the explanation that the words "in all things" mean not only in will, but in existence and being ( kata ten hyparxin kai kata to einai). Not content with this, Basil, George of Laodicea, and others published a joint explanation (Epiph., lxxiii, 12-22) that "in all things" must include "substance";

The court party arranged that two councils should be held, at Rimini and Seleucia respectively. At Seleucia (359) the Semiarians were in a majority, being supported by such men as St. Cyril of Jerusalem, his friend Silvanus of Tarsus, and even St. Hilary, but they were unable to obtain their ends. Basil, Silvanus, and Eleusius, therefore, went as envoys to Constantinople, where a council was held (360) which followed Rimini in condemning homoiousios together with homoousios, and allowed homoios alone, without addition. This new phrase was the invention of Acacius of Cæsarea, who now deserted the extremer Arians and became leader of the new "Homoean" party. He procured the exile of Macedonius, Eleusius, Basil, Eustathius, Silvanus, Cyril, and others.

Constantius died at the end of 361. Under Julian the exiles returned. Basil was probably dead. Macedonius organized a party which confessed the Son to be kata panta homoios, while it declared the Holy Ghost to be the minister and servant of the Father and a creature. Eleusius joined him, and so did Eustathius for a time. This remnant of the Semiarian party held synods at Zele and elsewhere. The accession of Jovian, who was orthodox, induced the versatile Acacius, with Meletius of Antioch and twenty-five bishops, to accept the Nicene formula, adding an explanation that the Nicene Fathers meant by homoousios merely homoios kat ousian. Thus Acacius had taken up the original formula of the Semiarians. In 365 the Macedonians assembled at Lampsacus under the presidency of Eleusius, and condemned the Councils of Ariminum and Antioch (360), asserting again the likeness in substance. But the threats of the Arian emperor Valens caused Eleusius to sign an Arian creed at Nicomedia in 366. He returned to his diocese full of remorse, and begged for the election of another bishop; but his diocesans refused to let him resign. The West was at peace under Valentinian, so the Semiarians sent envoys to that emperor and to the pope to get help. Liberius refused to see them until they presented him with a confession of faith which included the Nicene formula. He seems to have been unaware that the party now rejected the Divinity of the Holy Ghost; but this was perhaps not true of the envoys Eustathius and Silvanus. On the return of the legates, the documents they brought were received with great joy by a synod at Tyana, which embraced the Nicene faith. But another synod in Caria still refused the homoousion. For the rest of the history of the sect, who are now to be called Macedonians, see PNEUMATOMACHI.

In addition to bibliography under ARIANISM and BISHOP EUSEBIUS OF NICOMEDIA, see articles Basilius of Ancyra, Eleusius, Eustathius of Sebaste by Venables in Dict. Christ. Biog.; LICHTENSTEIN, Eusebius von Nikomedien (Halle, 1903); LOOFS, Eustathius von Sebaste und die Chronologie der Basilius-Briefe (Halle, 1898).

John Chapman.