Pedro de Avendaño a Spanish soldier that had arrived in Chile with the army of García Hurtado de Mendoza in 1557. He distinguished himself in the Battle of Millarapue. He later served in the garrison of Cañete under captain Alonso de Reinoso. Reinoso eventually found an Indian who betrayed the location of the fugitive Mapuche toqui Caupolicán. Avendaño, with 50 men and the traitorous Indian as a guide, marched in stormy weather into the mountains to Pilmaiquén and captured Caupolicán as he was planning a new counter-offensive against the Spanish, near the modern Antihuala, on February 5, 1558. He brought the toqui back to Cañete where he was eventually executed by empalement at the order of corregidor Reinoso.
Given an encomienda in Purén, his bad treatment of the natives in his charge was infamous among the Mapuche. During the short interim governorship of Rodrigo de Quiroga following the departure of Mendoza, in July 1561, Avendaño and two other Spaniards were ambushed and killed and their heads taken by a group of Mapuche under Guenupilqui near Purén. News of this killing and the display of the heads, triggered the second great Mapuche revolt in the Arauco War.