Portal:Argentina/Anniversaries/May/May 20

• 1591: Establishment of La Rioja
• 1780: Birth of president Bernardino Rivadavia
• 1810: Juan José Castelli requests an open cabildo to viceroy Baltasar Hidalgo de Cisneros
• 1946: Ill with diabetes, President Roberto María Ortiz is replaced by vicepresident Ramón Castillo