In this essay I set out to investigate the differences between the creed that was formulated at the council of Nicaea (325 A.D) and the creed that was produced at the council of Constantinopel (381 A.D). The majority of the differences are caused by the fact that the second of the two creeds isn?t based on the the first in text although it?s producerers thought of it as a confirmation of the first with an elaborated theology about the Spirit. This theological elaboration was made in accordance to the theology of the holy Spirit developed by the Capadocian theologians..