- 1272 – The first session of the Second Council of Lyon was held to discuss, among others, the pledge by Byzantine Emperor Michael VIII Palaiologos to end the Great Schism and reunite the Eastern church with the West.
- 1763 – Chief Pontiac (pictured) of the Ottawa Native American tribe led an attempt to seize Fort Detroit and drive out the British settlers, beginning Pontiac's Rebellion.
- 1895 – Alexander Stepanovich Popov presented his radio receiver, refined as a lightning detector, to the Russian Physical and Chemical Society.
- 1915 – World War I: The German submarine Unterseeboot 20 torpedoed and sank the ocean liner RMS Lusitania, killing 1,198 on board.
- 1920 – Soviet Russia recognized the independence of the Democratic Republic of Georgia by signing the Treaty of Moscow, only to invade the country six months later.
