There are proofs that it has given importance, however, these importance are not the same as that of the formal teachings. During the early existence of churches, the Holy Spirit was acknowledge and witnessed through baptismal formula and in the Apostles Creed. Also, when we use the threefold name, the father, the son and the Holy Spirit, we show that there is a practice and that the presence of the Holy Spirit is indeed acknowledged. But then, when it comes to literature, the Holy Spirit is not prominent enough and given little importance.
Montanism brought the subject into life and gave prominence to the Holy Spirit. This movement appeared in Phrygia by Priscilla and Maximilla. They announced the coming of anew period wherein there will be new revelations from God and called the whole period Paraclete and themselves as the prophers. The high morality being emphasized in this movement attracted others to join hence, the two preached about the nearness of death and the end of the world. This movement is more of an orthodox one and in contrast of Gnosticism.
However, because of several issues, the movement was rejected and the doctrine of the Holy Spirit remained undeveloped and with no formulation. It was Monarchianism which taught more about the fact that the Son was the expression of the father. Because of this, the Church was forced to know the relationship between the Spirit and the Son, as well as to the father. There it was revealed that God reveals himself in different forms which are three roles that he plays as God. It was Sabellanism which made a major error in interpreting the trinity and the Holy Spirit.
Aside from this error is the Arian controversy which is an anti-Trinitarian and does not agree with the Trinitarian views. The controversy in Nicea had to be brought into the Council of Constantinople. However, in this place another controversy came out which even made a great misunderstanding of the Doctrine. The people who were already confused started to disbelief the Doctrine and the Holy Spirit and one Bishop from Constantinople claimed that the Spirit is indeed a creature made subordinate to the Son. The orthodox on this movement preaches that the Holy Spirit is Divine and then the Son is not Divine of Vice Versa.
The creed was studied by the Council and pointed out that the creed made use of a term that will avoid another term of the substance. Hence this discovery did counter what the above movement had mentioned about the divinity of the Trinity. However, despite of the fact that the questions regarding the Deity were all cleared and understood by many, there are still questions about the importance and the mystery of the Spirit and its relation to the Son and the Father. In the west part, this one was the question raised by the people and two terms were used to describe the relationship between the Son to the Father and the Spirit.
Generation was used to describe the relation between the father and the son while Procession was used between the Son and the Father. In this period, three things were settled concerning the Holy Spirit and the Doctrine. Before Reformation, the attention of the church was focused into the Spirit alone but during the Reformation, the attention of the people and the church was focused on the works of the Holy Spirit. It was emphasized the Holy Spirits work has something to do with regenerating man. Several creeds and documents which grew out through reformation just like other periods, there are oppositions and exceptions.
The church history saw the formulation of the orthodox doctrine of the Holy Spirit first followed by the definition of the Holy Spirit and its relations to the father and the son through the councils and it was developed during Reformation. It was not an easy way because in ever discovery comes another opposition but in the end, the mystery of the Holy Spirit became known to the people. However, in this life, maybe it is how one sees the power of the Holy Spirit that makes its application and understanding worthwhile. References Ryrie, Charles C. The Holy Spirit