The Arauco War was a long-running conflict between colonial Spaniards and the Mapuche people, mostly fought in the Araucanía region of Chile. The conflict began at first as a reaction to the Spanish conquerors attempting to establish cities and force Mapuches into servitude. It subsequently evolved over time into phases comprising drawn-out sieges, slave-hunting expeditions, pillaging raids, punitive expeditions, and renewed Spanish attempts to secure lost territories. Abduction of women and war rape was common on both sides.
After many initial Spanish successes in penetrating Mapuche territory, the Battle of Curalaba in 1598 and the following destruction of the Seven Cities marked a turning point in the war leading to the establishment of a clear frontier between the Spanish domains and the land of the independent Mapuche. From the 17th to the late 18th century a series of parliaments were held between royal governors and Mapuche lonkos and the war devolved to sporadic pillaging carried out by both sides.
In the words of Philip II, this conflict cost the largest number of Spanish lives in the New World, which is why it became known as the Flandes indiano ("Indian Flanders"), in reference to the Eighty Years' War.
Causes of its origin and length
Initially, the key area of conflict that the Spanish attempted to secure south of Bío Bío River were the valleys around Cordillera de Nahuelbuta. The Spanish designs for this region was to exploit the placer deposits of gold using Mapuche (slave) labor from the densely populated nearby valleys. To serve the Spanish in gold mining was a deadly activity that killed many Mapuches. Lacking a tradition of forced labor like the Andean mita the Mapuches largely refused to serve the Spanish setting the stage for the conflict. It has been conjectured that gold mining was already occurring in Mapuche lands south of the Inca Empire prior to the Spanish arrival and that this would have allowed the Spanish to rapidly identify places with gold.
On the other hand, the Spanish, in particular those from Castile and Extremadura, came from an extremely violent society. According to Diego de Rosales 17th-century Mapuche chief Lientur would have explained that he preferred to "die warring, than in a bad peace". Analysing the situation in the 1650s the Real Audiencia of Santiago opined that slavery of Mapuches was one of the reasons for constant state of war between the Spanish and the Mapuches.
Jesuits sought to diminish hostilities and end the war altogether by converting Mapuches to the Christian faith. They temporarily succeeded in enforcing the Defensive War (1612–1626) policy, but their conversions attempts foundered on Mapuche leaders staunch defense of polygamy which was unacceptable in the Catholic faith. This insistence on polygamy has been explained as Mapuche chiefs valuing it as a way to establish more alliances through marriage than monogamous marriage allows. Polygamy may also have been valued as important population strategy in war times when the Mapuche male population was unstable.
Spanish conquest
An antecedent of the Arauco War was the Battle of Reynogüelén, which occurred in 1536 between a detachment of Diego de Almagro's expedition and a large group of Mapuches, near the confluence of the Ñuble and Itata rivers. The beginning of the war comes with the campaigns of conquest of Pedro de Valdivia.
Campaigns of Pedro de Valdivia (1546–1553)
During the early phase of the Conquest of Chile, the Spanish conquistador Pedro de Valdivia conducted a nine-year campaign to secure the city of Santiago, which had been destroyed on September 11, 1541 by the Mapochoes under the direction of their chief, Michimalonco. Valdivia hoped to enlarge the territory under his jurisdiction and, despite injuries from a fall from his horse, resolved to take personal command of a land expedition into Araucanía.
In 1544, a naval expedition was sent, comprising the barks, San Pedro and Santiaguillo, under the command of Juan Bautista Pastene, to reconnoiter the southwestern coast of South America to the Strait of Magellan. The expedition set sail from Valparaíso, entered the bay of San Pedro, and made landings at what is now known as Concepción and at Valdivia, which was later named in honor of the commander. Encountering severe storms further south, he then returned to Valparaiso.