Here are some thought provoking words on Jesus in history: the historic events are open to historical understanding, and at the same time are only understood by faith.
The Jesus of whom the Gospels tell us is a unique event in history, not to be confused with other personalities in history. His uniqueness in this general historical sense is an essential part of the fundamental confession of the Christian faith. …
The atonement and redemption which was achieved through the death of Jesus Christ on the Cross is an event which does not lie in the dimension of the historian. It is for that reason not something which the historian as such can recognize, but which is only apprehended by faith. It is an action of God, an act of the self-disclosure and self-communication of God, and thus is something which cannot be perceived as a historical occurrence. While the uniqueness which the historian apprehends in the Person and history of Jesus is only something relatively unique, that which faith apprehends in this historical fact as God’s deed and God’s Word of atonement and redemption is something absolutely unique, it is something that by its very nature either has happened once and for all, for all times and for every man, or else has not happened.
From Emil Brunner’s Dogmatics, Volume III.