The Ecclesiastical History of Sozomen

At this period the adherents of Macedonius, among whom were Eleusius, Eustathius, and Sophronius, who now began openly to be called Macedonians, as constituting a distinct sect, adopted the bold measure on the death of Constantius, of calling together those of their own sentiments who had been convened at Seleucia, and of holding several councils. They condemned the partisans of Acacius and the faith which had been established at Ariminum, and confirmed the doctrines which had been set forth at Antioch, and afterwards approved at Seleucia.

When interrogated as to the cause of their dispute with the partisans of Acacius, with whom, as being of the same sentiments as themselves they had formerly held communion, they replied by the mouth of Sophronius, a bishop of Paphlagonia, that while the Christians in the West maintained the use of the term “consubstantial,” the followers of Aëtius in the East upheld the dogma of dissimilarity as to substance; and that the former party irregularly wove together into a unity the distinct persons of the Father and of the Son, by their use of the term “consubstantial,” and that the latter party represented too great a difference as existing in the relationship between the nature of the Father and of the Son; but that they themselves preserved the mean between the two extremes, and avoided both errors, by religiously maintaining that in hypostasis, the Son is like unto the Father. It was by such representations as these that the Macedonians vindicated themselves from blame.