Jesus Christ is the major deity in Christianity. He is one with God and the Holy Spirit, a tripartite identity explained in the Nicene Creed, passed in 325 A.D.
The Nicene Creed stated that the Father (God), the Son (Jesus Christ), and the Holy Spirit were all one in the same. Later Christians tried to understand the exact relationship between these three deities, which caused great disagreement within the church throughout the Byzantine period.
The Latin term filioque (and the son) was re-examined because it had a different meaning than the earlier Greek text. This disagreement began many of the different modern factions of Christianity.