What happened on 17 September?

14 events from the Ever-When timeline, ranked by how much they mattered.

1. 1945 Chinese Civil War (resumed) Communist victory drives the Nationalists to Taiwan and founds the PRC.
2. 1787 US Constitution Drafted in Philadelphia; oldest written national constitution still in use.
3. 14 Reign of Tiberius Augustus's stepson; second Roman Emperor.
4. 1950 Born: Narendra Modi BJP leader; Prime Minister of India from 2014.
5. 1978 Camp David Accords Sadat, Begin and Carter agree framework for Egypt-Israel peace at Camp David; Israel cedes Sinai for diplomatic recognition.
6. 1862 Battle of Antietam Bloodiest single day in American history (~22,700 casualties). McClellan halts Lee's first invasion of the North in Maryland; Lincoln uses the tactical Union outcome to issue the E
7. 1631 Battle of Breitenfeld Gustavus Adolphus of Sweden crushes Tilly's imperial army; saves Protestant cause in Germany.
8. 1944 Operation Market Garden Bold but failed Allied airborne attempt to seize Rhine bridges at Arnhem.
9. 1914 Race to the Sea Failed flanking manoeuvres on the Western Front end at the English Channel.
10. 1988 Seoul Summer Olympics Coming-out party for South Korea's democratisation and 'miracle on the Han'.
11. 2011 Occupy Wall Street Protesters occupy a Manhattan park against economic inequality, spawning a global 'we are the 99%' movement.
12. 1176 Battle of Myriokephalon The Seljuks defeat Manuel I Komnenos in Anatolia, ending Byzantine hopes of recovering the interior and confirming Turkish control of central Asia Minor.
13. 1809 Sweden cedes Finland to Russia After six centuries as Sweden's eastern half, Finland becomes an autonomous Grand Duchy under the tsar — the separation that lets a Finnish nation form.
14. 1656 Second Protectorate Parliament Cromwell's second parliament, purged of a hundred opponents before sitting, which went on to offer him the crown through the Humble Petition and Advice.