"Sugar" Ray Robinson, born Walker Smith, got his start in boxing at age 15 when he borrowed a birth certificate from his 18 year old friend and from that point on he was Ray Robinson. His career spanned 30 years with 85 amateur wins and no losses and a pro record of 173 -19 - 6 with 108 KOs. He picked up the "Sugar" nickname during an amateur bout.
Robinson was so good they had to create the term "pound for pound" so he could be appropriately ranked as the best fighter in the world. Still he conquered 5 weight classes during his career and remains amongst the greatest of all time.