1741 – Frederick II of Prussia defeated Maria Theresa’s forces at Mollwitz and conquered Silesia.
1790 – The U.S. patent system was established when U.S. President George Washington signed the Patent Act of 1790 into law.
1809 – Austria declared war on France and its forces entered Bavaria.
1814 – Napoleon was defeated at the Battle of Toulouse by the British and the Spanish. The defeat led to his abdication and exile to Elba.
1825 – The first hotel opened in Hawaii.
1862 – Union forces began the bombardment of Fort Pulaski in Georgia along the Tybee River.
1865 – During the American Civil War, at Appomattox, General Robert E. Lee issued his last order.
1866 – The American Society for Prevention of Cruelty to Animals (ASPCA) was incorporated.
1902 – South African Boers accepted British terms of surrender.
1932 – Paul von Hindenburg was elected president of Germany with 19 million votes. Adolf Hitler came in second with 13 million votes.
1938 – Germany annexed Austria after Austrians had voted in a referundum to merge with Germany.
1941 – In World War II, U.S. troops occupied Greenland to prevent Nazi infiltration.
1944 – Russian troops recaptured Odessa from the Germans.
1945 – German Me 262 jet fighters shot down ten U.S. bombers near Berlin.
1963 – 129 people died when the nuclear-powered submarine USS Thresher failed to surface off Cape Cod, MA.
1968 – U.S. President Johnson replaced General Westmoreland with General Creighton Abrams in Vietnam.
1972 – The U.S. and the Soviet Union joined with 70 other nations in signing an agreement banning biological warfare.
1973 – In Switzerland, 108 people died when a plane crashed while attempting to land at Basel.
1980 – Spain and Britain agreed to reopen the border between Gibraltar and Spain. It had been closed since 1969.
1994 – NATO warplanes launched air strikes for the first time on Serb forces that were advancing on the Bosnian Muslim town of Gordazde. The area had been declared a U.N. safe area.