- 536 Byzantine General Belisarius enters Rome while the Ostrogothic garrison peacefully leaves the city, returning the old capital to its empire.
- 1212 Frederick II (later also Holy Roman Emperor) crowned King of Germany in Mainz
- 1968 NLS (a system for which hypertext and the computer mouse were developed) is publicly demonstrated for the first time in San Francisco.
- 1990 Lech Wałęsa wins Poland's 1st direct presidential election in Poland
- 1992 Operation Restore Hope - US Marines land in Somalia
Alfred Tennyson's poem "Charge of the Light Brigade" published
On December 9, 1854
The first traffic lights are installed outside the Palace of Westminster in London. Resembling railway signals, they use semaphore arms and are illuminated at night by red and green gas lamps.
On December 9, 1868