Johannes Quasten, Patrology, vol. III: The Golden Age of Patristic Literature (Westminster: Christian Classics, 1990) 341-342.
Eusebius was a Christian thinker in the third-fourth centuries C.E. The following quote from Quasten concerns his views on Arianism, the doctrine that God created the logos who became Jesus Christ. Arianism was rejected at the Council of Nicaea in the fourth century C.E., in favor of the view that the Father and the Son are co-eternal and co-substantial, and yet one God.
The three books of [Eusebius'] work Ecclesiastical Theology represent a more detailed refutation of Marcellus [of Ancyra, whom the Arian Synod at Constantinople deposed in 336]. Written about 337 they are dedicated to the Arian bishop Flaccillus of Antioch (334-342)...Though there is good ground for the belief that Marcellus was Sabellianistic in tendency, the exposition of the doctrine of the Logos which Eusebius offers here as 'the theology of the Church' is certainly not more than an advanced subordinationism: the Son of God is not of the essence of the Father but of His free will and the Holy Spirit is not more than a creation of the Son. He remains convinced (2, 7, 12) that to recognize the true divinity of the Son means to sacrifice the oneness of the Godhead. (341-342)
Although Eusebius signed on to the Nicene Creed (after being excommunicated for heresy), he differed from it in certain respects. He denied that the Son and the Father were of the same essence, positing instead that the Son proceeded from the Father's free will (creative act?). He also did not want to compromise the oneness of the Godhead, which he thought the notion of the Son's divinity would do. And, unlike Trinitarians, he did not view the Holy Spirit as an eternal being, but rather as a creation by the Son.
Eusebius did not care much for "Sabellianism," the modalistic view that there was one God who manifested himself in three different offices: Father, Son, and Holy Spirit. A professor of mine once compared the Sabellian God to Al Gore: he was the Vice-President, the husband of Tipper, and something else I don't quite remember (amateur climatologist, perhaps). The Sabellian God is one person who acts in three different ways, whereas the Trinitarian God is three persons in one being.
Eusebius was not exactly a Trinitarian, for he didn't fully assent to the divinity of the Son and the Holy Spirit. But he wasn't a Sabellian either, for he didn't think that the "Son" and the "Holy Spirit" were offices that the one God performed. Rather, he viewed the Son as a person distinct from God.
Eusebius admired Constantine's efforts to bring unity to the church through the Council of Nicaea, and he signed on to the Nicene Creed. Yet, according to Karen Armstrong (perhaps not the best source, but she documents her narrative with primary sources, plus I like her clear presentation), Eusebius still campaigned against the Athanasian "orthodoxy" (Trinitarianism) that triumphed at Nicaea, thereby influencing the emperor to lift the ban on Arius in 327. And, while all but two bishops signed on to the Nicene Creed, most bishops held a position somewhere in between Arius and Athanasius, plus the Arians who signed the document continued to promote Arianism. Karen Armstrong, Jerusalem: One City, Three Faiths (New York: Alfred A. Knopf, 1996) 178-179.
It's amazing that a figure as prominent as Eusebius, whose writings are advertised in the Christian Book Distributors, was sympathetic to Arianism. It just shows that there wasn't a solid consensus about the nature of Christ up to the fourth century C.E. (though adherents to all sides would probably say that the entire first century church agreed with their position).
At the same time, I don't exactly go with the Da Vinci Code's version of history, nor with that of its detractors, for that matter. In the Da Vinci Code, Ian McKellen tells some grand narrative about how the early Christians believed Jesus was a mere mortal who married Mary Magdalene, but certain Christians at the Council of Nicaea suppressed that view to proclaim Jesus as divine. Critics of the Da Vinci Code have responded, however, that the Nicene Creed was not controversial, since only two bishops voted against it. When I was following the whole Da Vinci Code controversy, I wondered how there even was an Arian controversy, if the church was virtually unanimous in accepting the Nicene Creed.
It turns out that both sides were off-base. Against the Da Vinci Code is the fact that a belief in Jesus' divine status was widespread among Christians. Even Arius thought that Jesus was more than a mere mortal, since he portrayed him as the very logos who created the cosmos. The debate at Nicaea and Chalcedon was not over whether Jesus was divine or a mere mortal, but rather over how to conceptualize Jesus' divinity.
Against certain critics of the Da Vinci Code, however, the fact that only two bishops voted against the Nicene Creed does not indicate that the vast majority of Christians agreed with it. There was strong political pressure to arrive at a consensus, and the consensus wasn't even that solid after the Council of Nicaea had reached its decisions.
As I read about the differences between the views of prominent Christians (e.g., Justin Martyr, Tertullian, and now Eusebius) and those of "orthodox" Trinitarians, I wonder if Christians should be so quick to condemn Jehovah's Witnesses, who have a different view of Jesus than most of Christianity. (For some reason, Christians on my Christian dating site tend to tolerate oneness Pentecostalism, the view that Jesus is the only God. But once someone says that Jesus was a created being or became Son of God at his baptism or resurrection, watch out! The heresy police gets into gear!)
At the same time, can I say that the issue of Jesus' divinity doesn't matter, considering that John 8:24 says that those who don't believe Jesus is "I AM" (God?) will die in their sins? And yet, are there ways to see Jesus as divine outside of the traditional Trinitarian formula? There were Christian thinkers in the second-fourth centuries who held to Jesus' divinity, while also denying that he was an eternal being!