Pope Gregory XIII issued a papal bull introducing the Gregorian calendar reform.
The Supreme Court ruled in Marbury v. Madison that any act of Congress which conflicts with the Constitution is null and void.
Mexico declared its independence from Spain.
Andrew Johnson, 17th president of the United States, became the first president to have impeachment proceedings brought against him by the House of Representatives.
The lease for Guantanamo Bay, Cuba, was signed.
Adolf Hitler outlined the basic points of the Nazi party at the Hofbrauhaus in Munich.
The discovery of a pulsar was announced.
The U.S. hockey team defeated Finland to win the gold medal at the Lake Placid Olympics.