We have two sources for Spartacus: Plutarch of Chaeronea and Appian of Alexandria. Both were written a century after he died. The two accounts mostly agree, but in the middle of the story they go completely different directions and then meet up again for the ending.

Spartacus is generally regarded as existing. We don’t know which account had it right, and it’s possible neither of them are. We will probably never know.

Point is, if you’re not a ruler, then historical evidence of your existence tends to be thin. Jesus likely existed, and we have better evidence for him than Spartacus.