Um...100%. History backs up the fact that there was a man named Jesus, born to Mary and Joseph in Bethlehem. Everything else is foggy, but Jesus was indeed a person.
I wouldn't go this far. The only other first century texts to affirm the historical existence of Jesus outside of Christian literature were written by the Jewish historian Josephus. But, even in this case, some scholars have suspected that the passages in Josephus affirming Jesus' existence were later interpolations. But, I don't think the latter suspicion, even if true, matters much. The development and flourishing of the Christian community in the first century really would not have been plausible if there weren't a real person who taught, healed, preached and was executed by Roman authorities and attracted so much attention and devotion. In addition to this, I don't think the relative uniformity of Jesus' sayings, especially as they are recorded in the synoptic gospels, would exist had such sayings not been attributable to a real person.
Bottom line: I think doubting that Jesus was a real historical person is wildly unreasonable, and that is why his existence is not questioned by other religious traditions, and only questioned very rarely and very implausibly by even the most secular of historians.
