Characteristic of the Enlightenment Era was the exaltation of human reason and natural explanations to the point of dismissing the miraculous or mysterious. The boundaries of truth were limited to what could be empirically known or rationally proved. "The Quest for the Historical Jesus" was undoubtedly influenced by such philosophical suppositions as scholars sought to deliniate between the historical Jesus and the Christ of faith.
Supernatural explanations for the imprint of Jesus left upon history and society were jettisoned in favor of more provable explanations. Since he could not have been a divine man who did miraculous works and was resurrected from the dead, there must be natural explanations for his ascendancy and for the lasting impact of the church.
Albert Schweitzer dated 1778 as the beginning of the "quest" with the controversial writings of Hermann Reimarus who dismissed the historicity of the resurrection accounts. Reimarus argued that Jesus died upon the cross disillusioned, having failed to usher in the kingdom of God. It was the creativity of his disciples that kept his legacy alive by reinterpreting his teachings eschatologically. The church contended that Jesus did not fail, but that he was resurrected and will return to set up his kingdom.
Many historical Jesus scholars followed, mainly within German academia, but also among the French and British. They were mostly consistent in their assesment that the historical Jesus was a peasant from Nazareth who failed to start a revolution and was instead crucified. He allegedly expected God's intervention to save him and to establish his kingdom on earth. When this did not happen, the church picked up the ball and reworked the doctrine of Christ with myths of a divine man, a resurrection, a spiritual kingdom, and a second coming.
The goal of the "quest" was to peel away the layers of church tradition and subsequent theological developments to get at the identity of the real man, Jesus of Nazareth. To really know what Jesus said and did meant getting back to the historical Jesus. The "Christ of faith" was allegedly an invention of the church since divine beings obviously don't walk the earth and there are no virgin births or resurrections. Everything must have a natural explanation. Historical Jesus scholars view the resurrection as the disciples' coping strategy to keep faith alive in one who was too great to die.
More recently, scholars like E. P. Sanders have stated it as fact that Jesus' followers had resurrection experiences. While he stops short of saying that the resurrection is a historical fact, he does not see faith as resulting from mass hysteria or "calculated deception." While more radical scholars say mass hysteria could account for 500 people who had a "resurrection experience" simulataneously, Sanders argues that this could not account for the numerous personal testimonies in the Gospel and Acts.
While radicals point to alleged contradictions in the Gospel accounts as proof of conspiracy, others argue that such an elaborate hoax would be more uniform. Conspirators would have made an effort to tidy up their accounts.
Even scholars who don't accept everything in the Gospels as historical are hard pressed to explain away the resurrection. Some are led to conclude that something extraordinary must have happened to launch such a movement as the church and to cause believers to embrace persecution or martyrdom rather than to deny the Christ of faith.
Bornkamm, Gunther, Jesus of Nazareth (New York: Harper & Row, 1956, 1960).
Brown, Colin, "Historical Jesus, Quest of" In Dictionary of Jesus and the Gospels, edited by Joel B. Green and Scot McKnight (Downers Grove, IL.: Intervarsity Press, 1992), 326-340.
Sanders, E. P., The Historical Figure of Jesus (London: Penguin Books, 1993, 1995).
Yancey, Philip, The Jesus I Never Knew (Grand Rapids: Zondervan, 1995). While not a Historical Jesus source per se, Yancey's book raises some good questions and gives plausible answers in regard to some of the issues relating to Jesus.