By 381 the Nicene position on the Son had largely prevailed in the East, and the argument had moved on. A party generally called the Pneumatomachi, the fighters against the Spirit, accepted that the Son was of one being with the Father but declined to say the same of the Holy Spirit, treating him as a ministering creature. The theologians of the previous generation, Basil of Caesarea and the two Gregories among them, had argued that this was incoherent: a creature cannot sanctify, and the Spirit is invoked in baptism alongside the Father and the Son.
The council called by Theodosius reaffirmed Nicaea and condemned the position. What is striking is how it did so. The creed associated with the council calls the Holy Spirit the Lord and giver of life, proceeding from the Father, worshipped and glorified together with the Father and the Son. Every phrase asserts divinity in practice, and the word homoousios is deliberately not used of the Spirit.
That restraint was probably tactical, an attempt to carry bishops who would not sign the strongest available formula. It has had a long life: the article on the Spirit is worded in terms of worship rather than metaphysics, and it is the article that has proved most durable across traditions with very different theological vocabularies. The council was attended by Eastern bishops only, with no representative of Rome, and its ecumenical status was recognised in the West afterwards rather than at the time.