CUILLAMACHU (kweel-yah-mah'-tchu), Arau-canian soldier, born in the Uthanmapu valley, Chili, in 1534; died in December 1603. He was cacique of Uthanmapu, and while very young joined, with the warriors of his tribe, the rest of the Araucanian army. Having taken part in many battles against the Spaniards, he was given the supreme command in 1593, and organized a large army at Lumaco. Two years later he attacked and took Fort Jesus, and then spread his forces about the districts near the Spanish settlements in 1594, causing them great troubles. In 1597 he took the important fortresses of Puren and Lumaco, and on 22 November 1598, surprised in an ambuscade the governor of Chili, Loyola (a nephew of the founder of the Jesuit order), who was crossing the Curalava valley with his family, sixty officers, and three priests, the whole party perishing after a desperate resistance. Cuillamachu immediately ordered that not only all the Araucanians, but the Cuncos and Guilliches also, rise in arms to kill every Spaniard or Creole found outside of the fortified cities or towns ; and during the year he closely invested the cities of Osorno, Vald[via, Villarrica, Imperial, Canete, Angol, and Coya, as well as the fortress of Arauco. In the mean time he crossed Biobio River, burned the cities of Concepcion and Chillon, pillaged every populated place in those provinces, and returned to his quarters with a large booty.

The royal troops under General Quinones had several indecisive encounters in 1599 with the Araucaniarts along the banks of the Biobio, especially at Yumbel, where 2,000 Indians under the cacque made a determined resistance against 2,000 Spanish soldiers. On 24 November at daybreak, he crossed Callavalla River, at the head of 4,000 men, surprised the City of Valdivia, and obtained plunder valued at nearly two million dollars. He then set fire to the buildings, killed many of the people, attacked the ships in the harbor, and returned to his quarters, near the Biobio, with all the Spanish artillery and war material, and over 400 prisoners. In 1600 a Dutch expedition tried to land at Valdivia; but the cacique at once attacked and drove it away. In 1602 the Indian chieftain took possession of the City of Villarrica, which had been closely besieged for nearly three years, and the cities of Osorno and Imperial also surrendered to him in 1603. Cuillamachu was the most famous of the Araucanian generals, and the Spaniards conquered the only one that succeeded in reestablishing independence in his country after it. In his long career as a warrior he was wounded forty-four times. On one occasion the governor of Chili invited him to negotiate for peace" but he answered that he would never submit to a foreign power while a drop of blood remained in the veins of his warriors.