April April 5–12 – Mount Tambora in the Dutch East Indies blows its top explosively during an eruption, killing upwards of 92,000, and propelling thousands of tons of aerosols (Sulfide gas compounds) into the upper atmosphere (stratosphere). The high level gases reflect sunlight, and cause the widespread cooling (known as a volcanic winter) and heavy rains of 1816, snows in June and July in the northern hemisphere, widespread crop failures, and subsequently famine, which is why 1816 is later known as the Year Without a Summer. April 21 – The eastern part of the former Garhwal Kingdom is joined with Kumaon division, under the administration of the British Raj. April 24 – The Second Serbian Uprising against Ottoman rule takes place in Takovo, Ottoman Serbia. By the end of the year Serbia is acknowledged as a semi-independent state; the ideals of the First Serbian Uprising have thus been temporarily achieved. May May 3 – Battle of Tolentino: Austria defeats the Kingdom of Naples, which quickly ends the Neapolitan War. Joachim Murat, the defeated King of Naples, is forced to flee to Corsica, and is later executed. May 30 – The Arniston, an East Indiaman ship repatriating wounded troops to England from Ceylon, is wrecked near Waenhuiskrans, South Africa, with the loss of 372 of the 378 people on board. June June 9 – The Final Act of the Congress of Vienna is signed: A new European political situation is set. The German Confederation and Congress Poland are created, and the neutrality of Switzerland is guaranteed. Also, Luxembourg declares independence from the French Empire. June 15 – The Duchess of Richmond's ball is held in Brussels, "the most famous ball in history". June 16 Napoleonic Wars – Battle of Ligny: Napoleon defeats a Prussian army under Gebhard Leberecht von Blücher. Napoleonic Wars – Battle of Quatre Bras: Marshal Ney engages Arthur Wellesley, 1st Duke of Wellington, resulting in a tactical and strategic draw. June 18 – Napoleonic Wars – Battle of Waterloo: Arthur Wellesley, 1st Duke of Wellington, and Gebhard Leberecht von Blücher decisively defeat Napoleon. June 22 – Napoleonic Wars: Napoleon abdicates again; Napoleon II (1811–1832), age 4, rules for two weeks (22 June to 7 July). June 26 – Napoleonic Wars: Wellington's advancing Allied Army takes Péronne, Somme on its way to Paris. July July 8 – Napoleonic Wars: Louis XVIII returns to Paris, and is 'restored' as King