In 325 , the Council of Nicaea adopted the Nicene Creed which described Christ as `` God of God , Light of Light , very God of very God , begotten , not made , being of one substance with the Father '' .
About a century later , in 325 , the First Council of Nicaea established the doctrine of the Trinity as orthodoxy and adopted the Nicene Creed that described Christ as `` God of God , Light of Light , very God of very God , begotten , not made , being of one substance ( homoousios ) with the Father . ''