The Council deemed the Creed cannot be altered without a Council. This is to ensure that the profession of faith is othrodox as approved by all Bishops. The issue with the Filioque has a lot to do with the West adding the Filioque on their own, and then later on using it to tell the East they are heretics for not having the Filioque. Some Eastern theologians do not have theological problems with the Filioque, though most still do. But there is a common rejection to the Filioque because it was added outside the approval and acceptance by bishops outside the West.
The Visigoths in Spain were in hot water then? Quoting again the
Credimus:
We believe in one God, the Father Almighty, maker of heaven and earth,
creator of all things visible and invisible.
And in one Lord, Jesus Christ, the only-begotten Son of God, and born of the Father before all ages.
God from God; Light from Light; true God from true God; born, not made,
omousion to the Father;
that is, of the same substance with the Father; through whom all things were made,
which are in heaven and which are on earth. Who for us men, and for our salvation, came down from heaven, and was incarnate by the Holy Spirit of the virgin Mary, and became man.
He suffered under Pontius Pilate, was buried, rose again on the third day, ascended into heaven, and sits at the right hand of God the Father
almighty. From thence He shall come to judge the living and the dead; whose kingdom shall have no end.
And in the Holy Spirit, the Lord, the Giver of life, also proceeding from the Father
and the Son (
et Filio - not
Filioque). With the Father and the Son to be adored and conglorified; who spoke through the prophets.
And in one, holy, catholic and apostolic Church.
We confess one baptism for the remission of sins.
We look for the resurrection of the dead, and the life of the world to come.
Amen.
Oh, and the Armenians.
We believe in one God, the Father Almighty, the maker of heaven and earth, of things visible and invisible.
And in one Lord Jesus Christ, the Son of God, the begotten of God the Father, the Only-begotten, that is of the essence of the Father.
God of God, Light of Light, true God of true God, begotten and not made; of the very same nature of the Father, by Whom all things came into being, in heaven and on earth, visible and invisible.
Who for us humanity and for our salvation came down from heaven, was incarnate, was made human, was born perfectly of the holy virgin Mary by the Holy Spirit.
By whom He took body, soul, and mind, and everything that is in man, truly and not in semblance.
He suffered, was crucified, was buried, rose again on the third day, ascended into heaven with the same body, [and] sat at the right hand of the Father.
He is to come with the same body and with the glory of the Father, to judge the living and the dead; of His kingdom there is no end.
We believe in the Holy Spirit, in the uncreated and the perfect; Who spoke through the Law, prophets, and Gospels; Who came down upon the Jordan, preached through the apostles, and lived in the saints.
We believe also in only One, Universal, Apostolic, and [Holy] Church; in one baptism in repentance, for the remission, and forgiveness of sins; and in the resurrection of the dead, in the everlasting judgement of souls and bodies, and the Kingdom of Heaven and in the everlasting life.