October 17 is the 290th day of the year (291st in Leap years). There are 75 days remaining.
- 1469: Ferdinand of Aragon marries Isabella of Castile. Their marriage leads to a unification of Aragon and Castile in a single country, Spain.
- 1492: Christopher Columbus first sees land in the New World, an unknown Bahaman island he calls San Salvador.
- 1777: American troops defeat the British in Saratoga, New York
- 1800: England takes control of the Dutch colony of Curaçao.
- 1815: Napoleon arrives at Saint Helena.
- 1860: First British golf open.
- 1912: Bulgaria, Greece and Serbia declare war on Turkey, joining Montenegro in the First Balkan War.
- 1917: First British bombing of Germany in World War I.
- 1918: Yugoslavia declared a republic.
- 1931: Al Capone convicted for income tax evasion.
- 1933: Albert Einstein, fleeing Nazi Germany, moves to the US.
- 1941: For the first time in World War II, a German submarine attacks an American ship.
- 1945: After a coup, Juan Peron becomes dictator of Argentina.
- 1961: 200 Algerian protesters are massacred by the Paris police.
- 1967: Premiere of the musical Hair at Broadway.
- 1970: Anwar Sadat becomes president of Egypt.
- 1973: The OPEC starts an oil embargo against a number of western countries, considered to have helped Israel in its war against Syria. Beginning of the oil crisis.
- 1977: West German commandos storm and capture a hijacked plane in Mogadishu, Somalia.
- 1979: The Nobel Peace Prize is awarded to Mother Theresa.
- 1989: A major earthquake (7.1 on the Richter scale) hit the San Francisco Bay Area at 5:04pm for 20 seconds. The epicenter was at Loma Prieta. The aftermath was extensively televised.
- 1994: Draft peace treaty between Israel and Jordan.
- 1994: Peace treaty between the government of Angola and UNITA rebels.
- 1563: Jodocus Hondius, Dutch cartographer
- 1711: Jupiter Hammond, poet
- 1782: Niccolò Paganini, Italian violin player and composer
- 1898: Simon Vestdijk, Dutch writer
- 1912: Pope John Paul I
- 1915: Arthur Miller, American playwright
- 1918: Rita Hayworth, American actress
- 1968: Ziggy Marley, Jamaican reggae musician
Holidays and observances: