Hernan Cortés defeats Pánfilo de Narváez, sent by Spain to punish him for insubordination.

Hernán Cortés de Monroy y Pizarro Altamirano, 1st Marquis of the Valley of Oaxaca was a Spanish conquistador who led an expedition that caused the fall of the Aztec Empire and brought large portions of what is now mainland Mexico under the rule of the King of Castile in the early 16th century. Cortés was part of the generation of Spanish explorers and conquistadors who began the first phase of the Spanish colonization of the Americas.

The Battle of Cempoala was fought on 27 May 1520 at Cempoala, Mexico between the forces of Pánfilo de Narváez and the forces of Hernán Cortés, which were supported by Chinantec warriors.

Pánfilo de Narváez was a Spanish conquistador and soldier in the Americas. Born in Spain, he first sailed to the island of Jamaica in 1510 as a soldier. Pánfilo participated in the conquest of Cuba and led an expedition to Camagüey, escorting Bartolomé de las Casas.

May 20 is the 140th day of the year in the Gregorian calendar; 225 days remain until the end of the year.