Muhammad Ali (; born Cassius Marcellus Clay Jr.; January 17, 1942 – June 3, 2016) was an American professional boxer and activist. Nicknamed "the Greatest", he is regarded as one of the most significant sports figures of the 20th century and is often regarded as the greatest heavyweight boxer of all time. He held the Ring magazine heavyweight title from 1964 to 1970. He was the undisputed champion from 1974 to 1978 and the WBA and Ring heavyweight champion from 1978 to 1979. In 1999, he was named Sportsman of the Century by Sports Illustrated and the Sports Personality of the Century by the BBC.