The Battle of Penco, on March 12, 1550 was a battle between 60,000 Mapuche under the command of their toqui Ainavillo with his Araucan and Tucapel allies and Pedro de Valdivia's 200 Spaniards on horse and afoot with a large number of yanakuna inclucing 300 Mapochoes auxiliaries under their leader Michimalonco defending their newly raised fort at Penco. It was part of the Arauco War.