Early Christians had conflicting beliefs about the true identity of Jesus. One group who followed an early bishop known as Arius believed that Jesus was an extraordinary human being, but was not truly God himself. Arius believed that since Jesus was born of a woman, he could not have co-existed with God the father, and therefore was only human. He was later excommunicated for his teachings.
Still other Christians believed that Jesus was only God and not human. Since he was perfect and no human can ever be perfect, he could not be perfect. This group believed that Jesus cast no shadow, and left no foot prints when he walked. To them, he was merely an apparition, not really there.
The debate, and particularly the Arian heresy, were resolved at the Council of Nicea in 325 C.E. This council declared Arianism to be a heresy and decided that Jesus was in fact both God and man.
The Council expressed its holdings in the Nicean creed, which reads:
We believe in one God the Father Almighty, Maker of all things visible and invisible; and in one Lord Jesus Christ, the only begotten of the Father, that is, of the substance [ek tes ousias] of the Father, God of God, light of light, true God of true God, begotten not made, of the same substance with the Father [homoousion to patri], through whom all things were made both in heaven and on earth; who for us men and our salvation descended, was incarnate, and was made man, suffered and rose again the third day, ascended into heaven and cometh to judge the living and the dead. And in the Holy Ghost. Those who say: There was a time when He was not, and He was not before He was begotten; and that He was made out of nothing (ex ouk onton); or who maintain that He is of another hypostasis or another substance [than the Father], or that the Son of God is created, or mutable, or subject to change, [them] the Catholic Church anathematizes