 Alvarado's paternal grandfather was Juan Alvarado "el Viejo" ("the elder"), who was "comendador" of Hornachos, and his paternal grandmother was Catalina Messía.Pedro de Alvarado's uncle on his father's side was Diego de Alvarado y Messía, who was the "comendador" of Lobón, Puebla, and Montijo, "alcalde" of Montánchez, and lord of Castellanos and of Cubillana.Diego was a veteran of the campaigns against the Moors.