John L. Sullivan fought in a bare-knuckle boxing match that lasted 75 rounds before he won. That would take it out of you for sure... This was fatally the case with Sullivan who later died from a heart attack on February 2, 1918. He died, allegedly, with barely 10 dollars in his pocket. When Sullivan was buried, the ground was frozen so hard that they had to blast out the grave with dynamite. Jake Kilrain, who served as a pallbearer, said, Old John L. would have approved.