Translated by Bl. Jackson.
The heresy of Arius lowered the dignity of the Holy Ghost as well as that of the Son. He taught that the Three Persons of the Holy Trinity are wholly unlike one another both in essence and in glory. "There is a triad, not in equal glories;" "one more glorious than the other in their glories to an infinite degree." So says the Thalia, quoted in Ath. de Syn. S: 15. But the Nicene definition, while it was precise in regard to the Son, left the doctrine of the Holy Ghost comparatively open, (Pisteuomen eis to ;'Agion Pneuma,) not from hesitation or doubt, but because this side of Arian speculation was not prominent. (Cf. Basil, Letters cxxv. and ccxxvi. and Dr. Swete in D.C.B. iii. 121.) It was the expulsion of Macedonius from the see of Constantinople in 360 which brought "Macedonianism" to a head. He was put there by Arians as an Arian. Theodoret (Ecc. Hist. ii. 5) explains how disagreement arose. He was an upholder, if not the author, of the watchword homoiousion (Soc. ii. 45) (but many supporters of the homoiousion (e.g., Eustathius of Sebasteia) shrank from calling the Holy Ghost a creature. So the Pneumatomachi began to be clearly marked off. The various creeds of the Arians and semi-Arians did not directly attack the Godhead of the Holy Ghost, though they did not accept the doctrine of the essential unity of the Three Persons. (Cf. Hahn, Bibliothek der Symbole, pp. 148-174, quoted by Swete.) But their individual teaching went far beyond their confessions. The Catholic theologians were roused to the danger, and on the return of Athanasius from his third exile, a council was held at Alexandria which resulted in the first formal ecclesiastical condemnation of the depravers of the Holy Ghost, in the Tomus ad Antiochenos (q.v. with the preface on p. 481 of Ath. in the edition of this series. Cf. also Ath. ad Serap. i. 2, 10). In the next ten years the Pneumatomachi, Macedonians, or Marathonians, so called from Marathonius, bishop of Nicomedia, whose support to the party was perhaps rather pecuniary than intellectual (Nicephorus H.E. ix. 47), made head, and were largely identified with the Homoiousians. In 374 was published the Ancoratus of St. Epiphanius, bishop of Salamis in Cyprus, written in 373, and containing two creeds (vide Heurtley de F. et Symb. pp. 14-18), the former of which is nearly identical with the Confession of Constantinople. It expresses belief in to Pneuma to ;'Agion, Kurion, kai Zoopoion, to ek tou Patros ekporeuomenon, to sun Patri kai Hui& 254; sumproskunoi menon kai sundoxazomenon, to lalesan dia ton propheton. It is in this same year, 374, that Amphilochius, the first cousin of Gregory of Nazianzus and friend and spiritual son of Basil, paid the first of his annual autumn visits to Caesarea (Bishop Lightfoot, D.C.B. i. 105) and there urged St. Basil to clear up all doubt as to the true doctrine of the Holy Spirit by writing a treatise on the subject. St. Basil complied, and, on the completion of the work, had it engrossed on parchment (Letter ccxxxi.) and sent it to Amphilochius, to whom he dedicated it.
Reference address : https://www.elpenor.org/basil/holy-spirit.asp