1942 -- Born Cassius Clay on January 17, in Louisville, Kentucky.
1954 -- Begins training as a boxer after his bicycle is stolen. Over next six years, Clay wins six Kentucky Golden Gloves championships, two national Golden Gloves titles, and two AAU (Amateur Athletic Union) crowns.
1960 -- Clay wins light-heavyweight gold medal at the Summer Olympics in Rome, beating Poland's Zbigniew Pietrzykowski in a 5-0 decision. In October, he wins his first professional bout, against Tunney Hunsaker.
1964 -- On February 25, Clay goes up against favored Sonny Liston. In what will become his trademark, Clay begins taunting Liston, calling him an "ugly old bear," promising to "float like a butterfly, sting like a bee." Clay is credited with a knockout and becomes the heavyweight champion of the world after Liston fails to come out of his corner for the seventh round. Clay coins the phrase "I am the greatest!" -- a phrase for which he will forever be known.
On February 26, Clay joins Nation of Islam, and on March 6, he changes his name to Muhammad Ali.
1966 -- Citing his religious beliefs, Ali files for conscientious objector status and refuses to serve in U.S. military, which is involved in the Vietnam War at the time.
1967 -- The U.S. government denies his status. Ali is convicted of draft evasion, sentenced to a maximum five years in prison and fined $10,000. The New York boxing association takes back his titles and bans him from boxing for three years.
1970 -- The New York State Supreme Court orders his boxing license reinstated.
1971 -- In March, Ali fights heavyweight champ Joe Frazier in Madison Square Garden, but loses after 15 rounds, in a unanimous decision.
Later that year, Supreme Court rules in his favor, reversing the 1967 draft-evasion conviction, saying he should not have been drafted in the first place due to his religious beliefs.
1974 -- In January, Ali beats Frazier. Later that year, he beats George Foreman in the "Rumble in the Jungle," and reclaims world heavyweight champion title.
1975 -- Ali again faces Frazier, beats him in fight known as "The Thrilla in Manila."
1978 -- In Februrary, Ali loses heavyweight title to Leon Spinks; regains it six months later by beating Spinks.
1981 -- Ali loses a unanimous decision to Trevor Berbick. In December, he announces his retirement -- at age 39 -- ending his career with a professional record of 56 wins, 5 losses, 37 knockouts.
1984 -- He is diagnosed with Parkinson's disease.
1996 -- Ali carries the Olympic flame for Summer Games in Atlanta, Georgia.
1997 -- Sports Illustrated names Ali Sportsman of the Century.
2005 -- Ali is awarded the Presidential Medal of Freedom, the highest U.S. civilian honor, by then-President George W. Bush.
2009 -- Ali attends the inauguration of President Barack Obama.
2016 -- Dies June 3 in Phoenix, Arizona. He was married four times and had nine children.
Sources: Biography, InfoPlease, History.com, ESPN.com
WATCH: Muhammad Ali Dies at Age 74