The dominant position among theologians in the early church was represented by Alexander, the bishop of Alexandria, who said:
"The Son is immutable and unchangeable, all-sufficient and perfect, like the Father, differing only in this one respect, that the Father is unbegotten. He is the exact image of his Father. Everything is found in the image which exists in its archetype; and it was this that our Lord taught when he said, 'My Father is greater than I.' And accordingly we believe that the Son proceeded from the Father; for he is the reflection of the glory of the Father, and the figure of his substance. But let no one be led from this to the supposition that the Son is unbegotten, as is believed by some who are deficient in intellectual power: for to say that he was, that he has always been, and that he existed before all ages, is not to say that he is unbegotten." Theodoret's Ecclesiastical History, book 1, chapter iv.
The opposing position was that of Arius, who said:
"We say and believe, and have taught, and do teach, that the Son is not unbegotten, nor in any way unbegotten, even in part; and that he does not derive his subsistence from any matter; but that by his own will and counsel he has subsisted before time, and before ages, as perfect God, and only begotten and unchangeable, and that he existed not before he was begotten, or created, or purposed, or established. For he was not unbegotten. We are persecuted because we say that the son had a beginning, but that God was without beginning. This is really the cause of our persecution, and likewise, beause we say he is from notheing. And this we say, because he is neither part of God, nor of any subjacent matter." Ibid., chapter v.
One historian summarized the difference in the two views this way:
"The single point where the difference lay was that Alexander held that the Son was begotten of the very essence of the Father, and is therefore of the same substance with the Father, while Arius held that the Son was begotten by the Father, not from his own essence, but from nothing; but that when he was thus begotten, he was, and is, of precisely the like substance with the Father.
"Whether the Son of God, therefore, is of the same substance, or only of like substance, with the Father, was the question in dispute. The controversy was carried on in Greek, and as expressed in Greek the whole question turned upon a single letter. The word which expressed Alexander's belief, is Homoousion. The word which expressed the belief of Arius, is Homoiousion. One of the words has two i's in it, and the other has but one." A. T. Jones, The Two Republics, pp. 333, 334.
The whole matter was settled at Nicea with the following resolution:
"We believe in one God, the Father Almighty, Maker of all things both visible and invisible.
"And in one Lord Jesus Christ, the son of God, begotten of the Father, only begotten, that is to say, of the substance of the Father, God of God, Light of Light, very God of very God, begotten, not made, being of one substance with the Father, by whom all things were made, both things in heaven and things in earth; who for us men, and for our salvation, came down, and was made flesh, and was made man, suffered, and rose again on the third day, went up into the heavens, and is to come again to judge the quick and dead.
"And in the Holy Ghost.
"But those that say, 'There was when he was not,' and 'Before he was begotten he was not,' and 'He came into existence from what was not,' or who profess that the Son of God is of a different 'person' or 'substance,' or that he is created, or changeable, or variable, are anathematized by the Catholic church."