It is becoming quite popular among Islamic dawagandists to claim that the Christians of the first four centuries did not worship the Holy Spirit as God, since this was something only agreed upon in the year 381 AD at the council of Constantinople. This was supposedly the time when the church officially decided to make or declare that the Holy Spirit is God, the third Person of the Trinity, and therefore co-equal to the Father and the Son. As the following Islamic website puts it:
Early on, Christians did not call the Holy Spirit “God”, nor did they worship or pray to the Holy Spirit. When did Christian theologians first insist on this same fully divine status for the Holy Spirit? The first such official statement is the creed of Constantinople in 381 CE. This creed attributed a number of things to the Holy Spirit, such as a divine title, ‘Lord’, and supreme worship equal to that rendered to the Father and the Son. Thus, the Holy Spirit was officially voted as the third Person of the Trinity. The Catholic Church admits:
The apostolic faith concerning the Spirit was announced by the second ecumenical council at Constantinople (381)  (Did the Early Church Fathers Believe in the Trinity? http://www.manyprophetsonemessage.com/2017/08/31/did-the-early-church-fathers-believe-in-the-trinity/)
It is clear from such statements that these Muhammadans have not read the primary sources for themselves, but are simply parroting the misinformation found in secondary and third sources, where they simple repeat the assertions made by anti-Trinitarian groups without ever bothering to verify the accuracy of those claims.