Template:On this day - March 21

Benito Juárez

• 525 – Dionysius Exiguus persuades the Papacy to fix the equinox on 21 March (the ecclesiastical spring equinox).
• 1222 – Alfonso X of Castile, only a few months old, is sworn heir to the throne of Castile in the city of Burgos (present-day Spain).
• 1534 – Pedro de Mendoza is appointed "adelantado" of the Río de la Plata (present-day Argentina).
• 1626 – Birth of Saint Peter of Saint Joseph Betancur, Spanish religious (d. 1667).
• 1721 – Death of Juan de Gaona y Abad, Spanish diplomat and aristocrat (b. 1658).
• 1806 – Birth of Benito Juárez, jurist and politician, President of Mexico on several occasions (d. 1872).
• 1836 – Birth of Jesús de Monasterio, Spanish violinist and composer (d. 1903).
• 1843 – Death of Guadalupe Victoria (José Miguel Ramón A. Fernández Félix), first President of Mexico (b. 1786).
• 1847 – Captain General Rafael Carrera officially establishes the Republic of Guatemala and becomes its first president.
• 1918 – A national Government is formed in Spain, headed by Antonio Maura, to face the grave situation created by the Defense Juntas.
• 1930 – In Chile, the Air Force, founded by Arturo Merino Benítez, begins to operate.
• 1937 – In Ponce (Puerto Rico), on the orders of the U.S. governor Blanton C. Winship, the police open fire on a peaceful demonstration, and 16 adults and a 13-year-old girl die (Ponce massacre). Because the police had surrounded the crowd, two policemen also die in the crossfire.
• 1947 – In Chihuahua (Mexico), the Colonial cinema opens on the site formerly occupied by the Betancourt theater.
• 1975 – In Greater Buenos Aires (Argentina), the Triple A perpetrates the Pasco massacre against militants of the Peronist Youth.
• 2004 – In El Salvador, Elías Antonio Saca (candidate of the ruling party ARENA) defeats Schafik Handal (candidate of the opposition party FMLN) with 57.71% of the vote in the presidential elections held that same day.
• 2018 – Pedro Pablo Kuczynski resigns the presidency of Peru in the third year of his term, the high point of the political crisis the country went through between 2017 and 2018.