“Filioque,” a Latin expression meaning “and the Son,” is of course a clause that was added by the Latin West to the Constantinopolitan Creed, originally formulated in Greek by the First Council of Constantinople in the year A.D. 381. This Creed of 381, in regard to the Holy Spirit, originally read:
“We believe in the Holy Spirit, the Lord, the Life-Giver, Who proceeds from the Father. With the Father and the Son, He is worshipped and glorified.”
The Western Church, first in A.D. 589 at the regional council of Toledo, amended this statement to include:
“We believe in the Holy Spirit, the Lord, the Life-Giver, Who proceeds from the Father and the Son (i.e., Filioque). With the Father and the Son, He is worshipped and glorified.”
Now, while it took quite some time for the Eastern Church to become aware of, and offended by, this Western amendment, it eventually became a serious bone of contention between Eastern and Westerner churchmen. And for good reason. For, in the original Greek text of the Constantinopolitan Creed of 381, the term “proceeds” (ekporeusis) had a specific and all-important meaning. It meant to originate from a single Source, Principal, or Cause (Aitia). And the single Source, Principal, or Cause of the Holy Spirit is of course the Father, and the Father alone. As St. Gregory of Nazianzus says …
“The Spirit is truly the Spirit proceeding (proion) from the Father, not by filiation, for It is not by generation, but by ekporeusis” (Discourse 39. 12).
Indeed, it was this very theology of the Cappadocian fathers (i.e., Sts. Gregory Nazianzus, Basil the Great, and Gregory of Nyssa) that the bishops at Constantinople I (381) intended to promote when they authored the Creed to say “The Holy Spirit …Who proceeds from the Father.” –a reference to the Father’s Monarchy as the sole Source, Principal, or Cause of the Spirit. And the bishops at Constantinople I did this to counter the heresy of the Macedonian Arians, who, at the time, were claiming that the Spirit is merely a “creation” of the Son.
‘No,’ said the Council fathers, ‘the Spirit is Divine and has His Source, like the Son, with the Father. It is from the Father that the Spirit proceeds.’
First of all, one needs to appreciate the authentic history of the A.D. 381 Council of Constantinople, which was not recognized in the West (or in the East) as ecumenical until about the time of the Council of Chalcedon in A.D. 451. In the wake of the Council of Nicaea (A.D. 325), Arianism experienced a dramatic resurgence in the East, with very limited impact on the West. By the 360’s, and especially with the election of Pope St. Damasus I in A.D. 367, the West was free from any native Arian influences. Not so in the East, however, where a large number of bishops were still Arians. Constantinople itself was a formally Arian see, with Arianism officially promoted by the Eastern Emperor Valens. But anyway On August 9, A.D. 378, Valens was killed and his army lost to an army of Goths led by Fritigern, whom Valens had given permission only two years earlier to settle in Roman territory.
So yes the heresy existed in the east and its historically documented.
God Bless, Gary