Events January–March January 8 – An unsuccessful slave revolt is led by Charles Deslondes, in St. Charles and St. James Parishes, Louisiana. January 17 – Mexican War of Independence – Battle of Calderón Bridge: A heavily outnumbered Spanish force of 6,000 troops defeats nearly 100,000 Mexican revolutionaries. January 22 – The Casas Revolt begins in San Antonio, Spanish Texas. February 5 – British Regency: George, Prince of Wales becomes prince regent, because of the perceived insanity of his father, King George III of the United Kingdom. February 19 – Peninsular War – Battle of the Gebora: An outnumbered French force under Édouard Mortier routs and nearly destroys the Spanish, near Badajoz, Spain. March 1 – Citadel Massacre in Cairo: Egyptian ruler Muhammad Ali kills the last Mamluk leaders. March 5 – Peninsular War – Battle of Barrosa: A French attack fails, on a larger Anglo-Portuguese-Spanish force attempting to lift the Siege of Cádiz in Spain. March 13 – Battle of Lissa: The British fleet defeats the French. March 22 – The Commissioners' Plan for Manhattan is presented. March 25 – The Great Comet of 1811 is discovered by Honoré Flaugergues. March 27 – Battle of Anholt: The British Navy defeats Denmark. March 28 – Henri Christophe is proclaimed King Henri I, turning the northern State of Haiti into the Kingdom of Haiti. April–June April 5–6 – Revolutionary riots occur in Buenos Aires. May 14 – Paraguay declares independence from the Spanish Empire (recognised May 15). May 16 – Peninsular War – Battle of Albuera: Spain, Portugal and Great Britain defeat the French. May 18 – Battle of Las Piedras near Las Piedras, Banda Oriental: The independentists of Uruguay gain their first victory. June 9 – The Great Podil fire breaks out in Kiev, Ukraine. June 10 – A volcanic eruption briefly creates Sabrina Island (Azores). June 15 – The Klågerup riots erupt in Sweden. July–September July 5 – Venezuela declares its Independence from the Spanish Empire. July 9 – British explorer David Thompson posts a notice at the confluence of the Columbia and Snake Rivers (in modern-day Washington), claiming the area for the United Kingdom. July 11 – The Russian Empire removes Anton II, Catholicos-Patriarch of All Georgia, from his office, placing a Russian-appointed bishop at the head of the Georgian church. July 14 Italian scientist Amedeo Avogadro publishes his memoir about the molecular content of gases. David Thompson reaches