The teaching on the Holy Spirit was expanded by the first Council of Constantinople (A.D. 381). History of Filioque
And in the Holy Spirit, the Lord, the Giver of Life, who proceeds from the Father; who with the Father and the Son together is worshiped and glorified; who spoke by the prophets. In one Holy, Catholic, and Apostolic Church. I acknowledge one Baptism for the remission of sins. I look for the resurrection of the dead, and the life of the world to come. Amen.
In A.D. 587, the local council of Toledo (Spain) added filioque to the Creed as an attempt to combat Arianism. (The Latin word filioque is translated in English as 'and the Son' and changes the Symbol of Faith) History of Filioque
And in the Holy Spirit, the Lord, the Giver of Life, who proceeds from the Father; who with the Father and the Son together is worshiped and glorified and in the Holy Spirit, the Lord, and the Giver of Life, who proceeds from the Father and the Son; who with the Father and the Son together is worshiped and glorified.
This addition was intended to emphasize the consubstantiality of the Father and Son against the Arian heresy. From Spain, ‘filioque’ spread to the Franks (present-day France). It was embraced by Charlemagne who went so far as to accuse the East of having deliberately omitted it from the ancient Creed. Pope Leo III (795-816) intervened, and forbade any interpolations or alterations in the Nicene Creed. He ordered the Creed, without filioque, to be engraved in Latin and Greek on two silver plates on the wall of St. Peter’s in Rome. Nevertheless, the addition was maintained by the Franks. The dispute grew (many historians think Charlemagne used the filioque in an attempt to justify his claim to be emperor against the Emperor of the Roman Empire located in Constantinople) between East and West and was the focus of the council of Constantinople which met A.D. 879-880. This council (recognized as the Eighth Ecumenical Council by Orthodox Christians) reaffirmed the creed of A.D. 381 and declared any and all additions to the creed invalid. This council’s teaching was affirmed by the patriarchs of Old Rome (John VIII), New Rome [Constantinople] (Photius), Antioch, Jerusalem, and Alexandria and by Emperor Basil I.
Still, filioque continued to be used by the Franks and spread to the Germans. The filioque began to be used in Rome, probably first at the coronation of Henry II in 1014. Historians see this as a passive acceptance by the pope (Benedict VIII) due to his reliance on the Germans for military protection. From that time, the Romans began adding the filioque to the creed and have continued doing so.
Therefore, it can be clearly seen that the Filioque was added by others in the west to adapt to problem that the Western Church was facing. This created a rift between the East and West and it also set up some problems with people who believed in the Councils themselves. If the Councils were called of God and if the men who were called by God to attend the Councils were impacted by the Holy Spirit, then why change their council after the fact? This problem has plagued certain aspects of the Western Church throughout history and becomes a precursor to the problems as the Bible is complied.
In an attempt to make things easier for people to understand and to make an universal truth more self evident to people who were learning bad teachings- the filoque was created and used.