QuickCheck: Is it true that Superman was not the first comic book superhero?

Superman is high on most people's list of early comic book heroes, though there were others who came before him.

SUPERHEROES are becoming household names, so much so that characters previously obscure to non-comic readers are getting their own TV shows today. At the very top of the mountain, after all these years, stands the greatest superhero of all time – The Man of Steel, Superman.

But is it true that Superman was not the first true superhero in pop culture?