Wikipedia:Selected anniversaries/September 14
- 786 - Harun al-Rashid (pictured) became the Abbasid caliph upon the death of his brother al-Hadi.
- 1752 - The British Empire adopted the Gregorian calendar, skipping eleven days (September 2 was followed directly by September 14).
- 1812 - Napoleon's invasion of Russia: Napoleon and his Grande Armée captured Moscow, only to find the city deserted and burning.
- 1959 - The Soviet spacecraft Luna 2 crashed onto and became the first man-made object to reach the Moon.
- 1960 - The Organization of the Petroleum Exporting Countries (OPEC) was founded by Iran, Iraq, Kuwait, Saudi Arabia and Venezuela.
Recent days: September 13 – September 12 – September 11
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