Template:On this day - March 20

José Joaquín de Olmedo

• 842 – Death of Alfonso II of Asturias, nicknamed "the Chaste", King of Asturias (present-day Spain) in 783 and between 791 and 842 (b. 760).
• 1179 – Alfonso VIII and Alfonso II, Kings of Castile and Aragon respectively, sign the Treaty of Cazola, by which both kingdoms divide between them the areas of reconquest in al-Andalus: Valencia, Denia and Játiva for Aragon, and the rest of the Muslim territories for Castile.
• 1254 – The Communities of Villages of Calatayud (present-day Spain) manage to constitute themselves as a Community by privilege of James I, King of Aragon.
• 1565 – Philip II of Spain entrusts Pedro Menéndez de Avilés with the conquest of the provinces of Florida (present-day United States) and the conversion of their natives to the Catholic faith.
• 1778 – By order of the Spanish Crown, the territories of the Province of Mendoza, the Province of San Juan and the Province of San Luis are separated from the Kingdom of Chile and incorporated into the Viceroyalty of the Río de la Plata.
• 1779 – In New Spain (present-day Mexico), the aqueduct that supplies water to Mexico City from Chapultepec is completed.
• 1780 – Birth of José Joaquín de Olmedo, poet, lawyer, politician, Deputy in the Cortes of Cádiz, and first Vice President of the State of Ecuador (d. 1847).
• 1814 – In Venezuela, the Battle of San Mateo is fought, in which Simón Bolívar commands the troops that defeat the royalists led by José Tomás Boves.
• 1814 – In Chile, the Battle of Membrillar is fought, where the Chilean forces of Juan Mackenna manage to temporarily halt the advance of the royalist army of Gabino Gaínza toward the Chilean capital.
• 1823 – In Spain, the Spanish Cortes, faced with the imminent invasion by the French troops known as the Hundred Thousand Sons of Saint Louis, decide to move themselves and the King from Madrid to Seville, and later to Cádiz, to lead a resistance movement similar to that of 1808.
• 1856 – At the Hacienda Santa Rosa (Costa Rica), President Juan Rafael Mora Porras gathers a group of Costa Rican soldiers who manage to expel the U.S. mercenary William Walker and his filibusters from the country.
• 1861 – In the city of Mendoza (Argentina), an earthquake occurs that destroys it completely.
• 1865 – In Madrid, disciplinary proceedings are opened against Emilio Castelar for writing the article "El rasgo", published in the newspaper La Democracia.
• 1878 – The Salgar–Wyse Agreement is signed between Colombia and France for the construction of the Panama Canal.
• 1882 – In Spain, reconstruction work begins on the Alcázar of Segovia.
• 1928 – The civil governor of Barcelona forbids young people under 18 from entering dance halls unless accompanied by a relative.
• 1932 – The German airship Graf Zeppelin inaugurates its regular flights to South America.
• 1946 – The Senate of Puerto Rico passes a bill restoring the use of the Spanish language as an official language.
• 1962 – In Argentina, President Arturo Frondizi decrees the federal intervention of the provinces of Buenos Aires, Chaco, Río Negro, Santiago del Estero and Tucumán, owing to the victory in those jurisdictions of supporters of the overthrown former president Juan Domingo Perón.
• 1990 – In the Philippines, the former first lady Imelda Marcos (widow of the dictator Ferdinand Marcos) is put on trial for bribery and misuse of government funds.
• 2016 – Barack Obama makes a presidential visit to Cuba after 88 years of the U.S. blockade of the island.