December 17 (December 17) is the 351st day of the year in the Gregorian calendar (352nd in leap years). There are 14 more days until the end of the year.
497. p. n. e. - The temple at the Roman Forum is dedicated to the god Saturn; the anniversary of this event is marked as Saturnalia.
1531 - An inquisition is established in the Portuguese capital, Lisbon, by order of Pope Clement VII.
1538 - Pope Paul III expels King Henry VIII of England from the Roman Catholic Church, having previously declared himself head of the Anglican Church.
1583 - Ernest of Bavaria defeats Gebhard von Waldburg in the Cologne War in the siege of Godesberg.
1903 - Brothers Wilbur and Orville Wright make the first successful airplane flight in the history of aviation. Their "Flyer I" spacecraft took off four times over the sand dunes near Kitty Hawk in North Carolina, USA, staying in the air for a maximum of 59 seconds.
1908 - After the victory of the Young Turk Revolution, the first session of the Ottoman Parliament is held.
1926 - In a coup in Lithuania, the army overthrows democratically elected President Kazis Grinius and replaces Antanas Smetona.
1939 - A German battleship, the Admiral Graf von Spee, sinks in La Plata Bay near Montevideo in World War II, previously damaged in battle with British cruisers. The ship's captain Hans Langsdorf then committed suicide.
1948 - In an attempt to re-establish independence in Indonesia, which declared independence in 1945, the Netherlands invades Indonesia, invades the capital Jakarta and arrests President Sukarno and other Indonesian leaders. By the Hague Agreement of 1949, the Netherlands recognized the sovereignty of Indonesia.
1960 - Soldiers loyal to Ethiopian Emperor Haile Selassie quell a coup attempt that begins on December 13.
1973 - Arab extremists kill 32 people at Rome airport when they drop a bomb on a Pan American plane and use machine guns to blow up a terminal building.
1983 - A Provisional Irish Republican Army detonates a car bomb outside Herods in London, killing six and wounding about 90 others.
1983 - A fire in a disco in Madrid kills 83 people.
1985 - A military agreement is signed by the Ugandan military and guerrillas to divide power and end the war.