There is an obvious solution to this problem that goes like this: Jesus's followers did not think of him as divine - they thought of him as a (special) man. As Christianity spread into the Greek world, new converts from pagan backgrounds imported polytheistic concepts into the religion. Later theologians reconciled these ideas with Jewish monotheism by inventing the Trinity.
This is a rather attractive hypothesis because it explains such a wide variety of mysteries about early Christianity: not just ideas about Jesus, but also Christian rituals like baptism and the Eucharist (or Lord's supper) can be seen as deriving from similar pagan practices. Atheists and other critics of Christianity who run across this idea often find it extremely attractive - what better put-down for Christian proseletizers than to respond, "Your whole religion is stolen from paganism!" They create websites and write books proclaiming their discoveries. Unfortunately, the hypothesis is almost completely false.
The pagan origins hypothesis has been around a long time - more than 100 years, in fact. It was popular among a group of scholars known as the "History of Religions School," because they sought the origin of Christianity in its connections to other religions.These scholars made many important contributions to our understanding of Christian origins. But, over the course of the past century, scholarship has swung back in the other direction. Important new discoveries, such as the Dead Sea Scrolls and the Nag Hammadi library, have changed our picture of ancient Judaism as well as of early Christianity. Many now see features previously thought to derive from paganism as coming from Judaism, albeit a Judaism that was already strongly influenced by the surrounding Greek culture. So, modern proponents of the pagan origins hypothesis are about 100 years out of date.
But how, then, did Jesus come to be seen as a god? As we saw in the last few posts, there was considerable room in "monotheistic" Judaism for belief in various supernatural entities apart from God. Among these we sometimes encounter a figure who acts on God's behalf, as a sort of ambassador or political agent of God. In Roman times, the ruler could not be present in all parts of his realm, and communication was slow. The only way to rule was by proxies who could travel in the emperor's place, and whose word was accepted as the word of the emperor. In various Jewish texts written around the time of Jesus, there are references to such a figure who could speak for God, bear God's name, even sit on God's throne. This figure is given a variety of names - the Great Angel, Metatron, the Logos (Word). The first-century AD Jewish writer, Philo, describes him this way:
God’s First Born, the Logos, who holds the eldership among the angels, their ruler as it were. And many names are his, for he is called “the Beginning,” and the Name of God and his Logos and the Man after his Image… (Philo, On the Confusion of Tongues 146)
Christians took all these terms and applied them to Jesus. A particularly important concept was Jesus as the Wisdom of God:
...Christ who is both the Power of God
and the Wisdom of God. (1 Corinthians 1:24)
As the Wisdom of God, Jesus could be from God, indeed even be a part of God, without taking God's place. And as God's agent-ambassador, he could speak for God without usurping God's place in Jewish monolatry.
Careful analysis of the New Testament texts indicates that it was a Jewish ladder, not a pagan one, that Jesus climbed to become part of the Trinity.(For more details on all of this, take a look at my essay, Promoted to God.) This is not to deny that, at times, Christian beliefs might have been influenced directly or indirectly by pagan religious and philosophical ideas - they certainly were. But the main lines of development of ideas about Jesus come straight out of contemporary Judaism.
If religion teaches us atheists one thing, it should be this: to be skeptical of claims that we want to believe. Some atheists seem to have fallen into the trap of believing in a pagan origin for Christianity because it suits their agenda, rather than on the basis of the evidence. We should instead be careful about all claims, until they are established on the basis of actual data and methodical scholarship.