Jesus.
No one can deny the impact of him on the world. Your beliefs concerning him puts you in one of 3 major earth religions. The vast majority if not all humans in existence today know the gist of his story. Even if you stand in opposition (i.e. athiests, bible scoffers, etc) if you stand in that position you stand contrary, contrasted, based upon HIM.
Hate it or love it the name still moved you.
Definitely a prime contender..
I mean...he is the reference point for measuring time for most of the modern world...doesn't get anymore influential than that.
Which is crazy considering he is still somewhat of a mythical figure, in science at least (correct me if I'm wrong).