Basil the Great of Caesarea
Gregory of Nyssa
Gregory of Nazianzus
So much of what we today consider “normal” in church and in doctrine comes out a struggle within the early church. The doctrine of the Trinity as formulated in the three ecumenical creeds came about in the battle against Arius.
Arius (256-336) was Bishop in Alexandria, Egypt. He questioned whether the second person always existed. By doing so, he challenged the fact of the New Testament that Jesus was truly God, and equal to the Father in the Godhead. The Council at Nicea in 325 was the first general council of the church catholic and one of the issues it dealt with was the teaching of Arius. The council condemned that teaching of Arius.
But the battle was far from over. The entire 4th century was one of turmoil in more clearly articulating the relationship of the Father and the Son (as well as the Holy Spirit). It was not a pretty sight in terms of instability, church fights, etc. (sounds almost like 2012). But the three Cappadocian fathers were instrumental in defending the Trinity based on the Scriptures. We give thanks to God for raising up these three to defend the faith.