He won the gold medal in the Olympic Games of 1968 in Mexico. As a pro he conquered the world heavyweight crown in 1973. He had two eras as an extraordinary hard hitting and then immensely intrepid fighter, shaping a professional record of 76 victories, 5 defeats-  one of them was against Muhammad Ali. He retired in 1977 returning  in 1987; amazingly becoming champion at forty five. An almost twenty year span! His final  farewell from the ring was in 1997. A great amongst greats!