Why did Constantine the Great force the false doctrine of the trinity on Christianity?
He didn’t. Tertullian (160-220) was the first person to use the specific word Trinity His teaching that the Father, the Son and the Spirit are one in essence was quite close to the view that the Church eventually adopted. This is of course the same view as the New Testament declares in Matthew 28:19-20 “Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.” Also, in Ephesians 4:4-6, we see the doctrine of the Trinity clearly enunciated again: There is one body and one Spirit—just as you were called to one hope when you were called— one Lord, one faith, one baptism; one God and Father of all, who is over all and through all and in all. Also, just to make things perfectly clear, the doctrine of the Trinity was not discussed at the Council of Nicea.
Constantine didn’t force the doctrine of the Trinity onto Christianity. The doctrine of the Trinity was officially promulgated by the 1st Council of Nicea in 325 which was convened by Constantine. One of the purposes of the Council was to rule on the Arian controversy. The Arians, who believed that Jesus was just a creation of the Father were in conflict with the Alexandrians, who believed that Jesus was begotten of the Father, not created. After looking at the Bible and examining church tradition, the Council decreed that the Arians were preaching heresy, and that The Father and The Son (and the Holy Spirit) are of the same essence and co-eternal: ie three in one – the Trinity. In Matthew 28:19, Jesus himself commanded his disciples to baptise people into Christianity in the Name of the Father, the Son and the Holy Spirit – one of the strongest biblical arguments for the Trinity.
