Complex sentence: Known as "The Hawk", Jackson is considered by many to be the pound for pound hardest puncher in boxing history, he is a former WBA light middleweight and two-time WBC middleweight champion.
Split into simpler sentences: Known as "The Hawk", Jackson is considered by many to be the pound for pound one of the hardest punchers in boxing history. He is a former WBA light middleweight and two-time WBC middleweight champion.