The Dew From Heaven
Subordinationism, the belief that Jesus was not equal, but subordinate to the Father, is found in both the bible and in the writings of the earliest Christians.
"The Father is greater than I" (John 14:28)
"God is the head over Christ" (1 Corinthians 11:3)
"the Son can to nothing by himself; he can only do what he sees the Father doing." (John 5:19)
"I don't do anything on my own. I only say what my Father taught me." (John 8:28)
There is wide consensus that before AD 355, everyone accepted subordinationism. ("The Search for the Christian Doctrine of God: The Arian Controversy", R.P.C. Hanson, pg 318-381)
"Be subject to the bishop... as Jesus Christ [was] subject to the Father." (Ignatius, Bishop of Antioch, "Epistle of Ignatius to the Magnesians" )
"The Father himself is alone called God, moreover the scriptures acknowledge him alone as God; and... the Lord confesses him alone as his own father and knows no other." (Irenaeus, Bishop of Rome,"Against Heresies")
Some... have become disciples of one Noetus, who was a native of Smyrna, and lived not very long ago... He alleged that Christ was the Father Himself, and that the Father Himself was born, and suffered, and died... Now they seek to exhibit the foundation for their dogma by citing the word in the law, "I am the God of your fathers; ye shall have no other gods before me;" and again in another passage, "I am the first," he saith, and the last; and beside me there is none other." Thus they say they prove that God is one. And then they answer in this manner: "If therefore I acknowledge Christ to be God, He is the Father Himself, if He is indeed God; and Christ suffered, being Himself God; and consequently the Father suffered, for He was the Father Himself." (Hippolytus)