So said John L. Sullivan, the "Boston Strong Boy," in 1889, and he had reason to feel that way: he may have entertained more people than any other American of his time. He created the role of heavyweight champion of the world, and it's hard to imagine how different the history of the title would be without him. And don't let the Victorian fighting pose fool you: this was one rough customer. He once battled for 75 rounds in 100-degree heat, more than two hours of fighting, and won. And he wasn't wearing gloves.