March 31, 1973 - Loses NABF title to Ken Norton in the twelfth round.

September 10, 1973 - Regains the NABF title in the twelfth round of the rematch with Ken Norton.

January 23, 1974 - Brawls with Joe Frazier at the New York studio of ABC, both fined $5,000.

January 28, 1974 - Defeats Joe Frazier in 12 rounds and retains his NABF title.

October 30, 1974 - "The Rumble in the Jungle" place in Kinshasa, Zaire (now Democratic Republic of the Congo). Ali defeats George Foreman, by KO in the eighth round, to again become the World Heavyweight Boxing Champion.

1975 - Leaves the Nation of Islam to practice the more mainstream Islamic faith.

October 1, 1975 - The "Thrilla in Manila," against Joe Frazier, is another victory when Frazier's manager, Eddie Futch, fearing for Frazier's safety, ends the match before the start of round fifteen.

February 15, 1978 - Loses his heavyweight title to Leon Spinks after fifteen rounds and a split decision.

September 15, 1978 - Regains title from Leon Spinks with a unanimous decision after fifteen rounds, becoming heavyweight champion of the world for the third time.

June 26, 1979 - Retires from professional boxing.

October 2, 1980 - Comes out of retirement for a guaranteed purse of $8 million, a chance for the World Boxing Council title and loses to Larry Holmes by KO in the eleventh round. First signs of Parkinson's are seen in public.

December 11, 1981 - Loses to Trevor Berbick, after ten rounds and a unanimous decision; this is his last professional fight.

1984 - Reveals that he has Parkinson's syndrome, a disorder of the central nervous system.

November 27, 1990 - Meets with Saddam Hussein in Baghdad, attempts to negotiate release of Americans held hostage in Iraq and Kuwait.

December 2, 1990 - Leaves Iraq with 14 hostages.

July 19, 1996 - Lights the torch at the opening ceremonies to the Summer Olympics in Atlanta.

February 4, 1999 - First boxer to appear on front of a Wheaties cereal box.

October 23, 2000 - Appointed United Nations Messenger of Peace.

November 9, 2005 - Presented with the Presidential Medal of Freedom by President George W. Bush.

November 21, 2005 - The Muhammad Ali Center opens in Louisville, Kentucky.

April 11, 2006 - Entertainment and licensing firm CKX announces that it is paying Ali $50 million in exchange for 80 percent of whatever it makes selling his name and likeness. Under the agreement, Ali has 20 percent control of the newly formed company G.O.A.T. LLC, which stands for "Greatest of All Time."

May 24, 2011 - Publicly appeals to Iranian officials for the release of captive hikers Shane Bauer and Josh Fattal.