(1) Leonardo Da Vinci vs. (4) Galileo
This matchup features two Italian guys who need no last names, much less introductions. Leonardo's going to come out on top in the diversity department; not only did he do a little bit of everything, he did all of it really well. Galileo is no pushover, though. He's got a strong claim to the position of "father of science," and he made huge strides in astronomy and physics. His work as a mathematician doesn't get as much publicity, but he was a big dog in that field, too. (Galileo's paradox famously concluded that although not all numbers are perfect squares, there are as many perfect squares as there are whole numbers. Try wrapping your head around that one.) Leonardo, though, had his own scientific observations and theories, and on top of that he was one of the greatest artists of all time. Tough call, but who's the bigger genius?
[See the whole bracket here.]