0451 – Roman and Barbarian warriors brought Attila’s army to a halt at the Catalaunian Plains in eastern France.
1397 – The Union of Kalmar united Denmark, Sweden, and Norway under one monarch.
1756 – In India, 150 British soldiers were imprisoned in a cell that became known as the "Black Hole of Calcutta."
1782 – The U.S. Congress approved the Great Seal of the United States.
1791 – King Louis XVI of France was captured while attempting to flee the country in the so-called Flight to Varennes.
1793 – Eli Whitney applied for a cotton gin patent. He received the patent on March 14. The cotton gin initiated the American mass-production concept.
1837 – Queen Victoria ascended the British throne following the death of her uncle, King William IV.
1863 – West Virginia became the 35th state to join the U.S.
1863 – The National Bank of Philadelphia in Philadelphia, PA, became the first bank to receive a charter from the U.S. Congress.
1898 – The U.S. Navy seized the island of Guam enroute to the Phillipines to fight the Spanish.
1910 – Mexican President Porfirio Diaz proclaimed martial law and arrested hundreds.
1910 – Fanny Brice debuted in the New York production of the "Ziegfeld Follies".
1923 – France announced it would seize the Rhineland to assist Germany in paying its war debts.
1941 – The U.S. Army Air Force was established, replacing the Army Air Corps.
1943 – Race-related rioting erupted in Detroit. Federal troops were sent in two days later to end the violence that left more than 30 dead.
1947 – Benjamin "Bugsy" Siegel was murdered in Beverly Hills, CA, at the order of mob associates angered over the soaring costs of his project, the Flamingo resort in Las Vegas, NV.
1948 – "Toast of the Town" debuted on CBS-TV. The show was hosted by Ed Sullivan.
1950 – Willie Mays graduated from high school and immediately signed with the New York Giants.
1955 – The AFL and CIO agreed to combine names and a merge into a single group.
1963 – The United States and Soviet Union signed an agreement to set up a hot line communication link between the two countries.
1966 – The U.S. Open golf tournament was broadcast in color for the first time.
1967 – Muhammad Ali was convicted in Houston of violating Selective Service laws by refusing to be drafted. The U.S. Supreme Court later overturned the conviction.
1977 – The Trans-Alaska Pipeline began operation.
1979 – ABC News correspondent Bill Stewart was shot to death in Managua, Nicaragua, by a member of President Anastasio Somoza’s national guard.
1983 – The U.S. Supreme Court ruled that employers must treat male and female workers equally in providing health benefits for their spouses.
1997 – The tobacco industry agreed to a massive settlement in exchange for major relief from mounting lawsuits and legal bills.
2001 – Barry Bonds (San Francisco Giants) hit his 38th home run of the season. The home run broke the major league baseball record for homers before the midseason All-Star break.
2002 – The U.S. Supreme Court ruled that the execution of mentally retarded murderers was unconstitutionally cruel. The vote was 6 in favor and 3 against.