Alonso de Estrada (ca. 1470, Ciudad Real, Spain – 1533-37, Mexico City) was a colonial official in New Spain during the period of Hernán Cortés's government, and before the appointment of the first viceroy. He was a member of the triumvirates that governed the colony for several short periods between 1524 and 1528, in the absence of Cortés.
Don Alonso de Estrada was an illegitimate son of King Ferdinand II of Aragon and Dona Luisa Estrada, daughter to Don Fernan Estrada, the Spanish Royal Ambassador to England, thereby making him a step-son to Isabella I of Castile. He was raised at court. He fought in the wars in Flanders, and afterwards, as an admiral, in the campaigns in Málaga and Sicily. Returning to Madrid, he fought in the Castilian War of the Communities, opposing the rebels against Emperor Charles V. For this, Charles rewarded him with the position of corregidor of Cáceres, and later named him treasurer of New Spain. In letters to the Spanish Crown by others, Alonso de Estrada was referred to as "el magnífico señor el thesorero Alonso de Estrada, gobernador de esta Nueva España por sus majestades.
Boasted that he was of royal blood, he came to New Spain in 1523, appointed treasurer of the colony by the Council of the Indies, on the authority of Charles V. His mission was to participate in the government of Cortés and to protect the interests of the Crown. Marcos de Aguilar and Luis Ponce de León (governor of New Spain) (colonial official) were also sent by the Crown to act as judges in the juicio de residencia of Cortés, but Ponce de León died of indigestion contracted at his welcoming banquet. Rumored to have been poisoned by Hernan Cortes.
Estrada was forceful and violent. Rumors of his royal parentage accompanied him to New Spain.
In 1524 Governor and Captain General Cortés left Mexico City for Honduras. He left the government in charge of Estrada, Rodrigo de Albornoz and Lic. Alonso de Zuazo. Zuazo (or Suazo) held the additional office of Justicia Mayor. The transfer of power occurred October 12, 1524. This triumvirate shared power with the ayuntamiento (city government). The ayuntamiento was composed of partisans of Cortés; Estrada and Albornoz were (or soon would be) his enemies. At one point Estrada issued orders to prevent the reentry of Cortés into Mexico City.