The main issue that prompted this dispute between Cyril and Nestorius was the question which arose at the Council of Constantinople: What exactly was the being to which Mary gave birth? Cyril affirmed that the Holy Trinity consists of a singular divine nature, essence, and being ("ousia") in three distinct aspects, instantiations, or subsistencies of being ("hypostases"). These distinct hypostases are the Father or God in Himself, the Son or Word ("Logos"), and the Holy Spirit. Then, when the Son became flesh and entered the world, the pre-Incarnate divine nature and assumed human nature both remained, but became "united" in the person of Jesus. This resulted in the miaphysite slogan "One Nature united out of two" being used to encapsulate the theological position of this Alexandrian bishop.