Later Alonso de Mendoza moved to Peru, where his natural intelligence, people skills, and personal charm opened the doors of the headquarters of Pizarro, then at war with his partner Diego de Almagro.
Mendoza's life took another dramatic turn when he decided to serve under the orders of Pedro de la Gasca, the envoy of the King, who entrusted him with a group of chivalry in the battle of Sacsahuaman.