Archaeological finds have shown the existence of a Mapuche culture in Chile and Argentina as early as 600 to 500 BC. Genetically Mapuches differ from the adjacent indigenous peoples of Patagonia. This suggests a "different origin or long lasting separation of Mapuche and Patagonian populations".
Troops of the Inca Empire are reported to have reached the Maule River and had a battle with the Mapuches between the Maule River and the Itata River there. The southern border of the Inca Empire is believed by most modern scholars to have been situated between Santiago and the Maipo River or somewhere between Santiago and the Maule River. Thus the bulk of the Mapuche escaped Inca rule. Through their contact with Incan invaders Mapuches would have for the first time met people with state organization. Their contact with the Incas gave them a collective awareness distinguishing between them and the invaders and uniting them into loose geo-political units despite their lack of state organization.
At the time of the arrival of the first Spaniards to Chile the largest indigenous population concentration was in the area spanning from Itata River to Chiloé Archipelago—that is the Mapuche heartland. The Mapuche population between Itata River and Reloncaví Sound has been estimated at 705,000–900,000 in the mid-16th century by historian José Bengoa.[note 1]
The Spanish entered Mapuche territory from Peru. Their expansion into Chile was an offshoot of the conquest of Peru. In 1541 Pedro de Valdivia reached Chile from Cuzco and founded Santiago. The northern Mapuche tribes, such as the Promaucaes and the Picunches, fought unsuccessfully against Spanish conquest. Little is known about their resistance.
In 1550 Pedro de Valdivia, who aimed to control all of Chile to the Straits of Magellan, traveled southward to conquer more Mapuche territory. Between 1550 and 1553 the Spanish founded several cities[note 2] in Mapuche lands including Concepción, Valdivia, Imperial, Villarrica and Angol. The Spanish also established the forts of Arauco, Purén and Tucapel. Further efforts by the Spanish to gain more territory engaged them in the Arauco War against the Mapuche, a sporadic conflict that lasted nearly 350 years. Hostility towards the conquerors was compounded by the lack of a tradition of forced labour akin to the Inca mita among the Mapuche, who largely refused to serve the Spanish.
From their establishment in 1550 to 1598, the Mapuche frequently laid siege to Spanish settlements in Araucanía. The war was mostly a low intensity conflict. Mapuche numbers decreased significantly following contact with the Spanish invaders; wars and epidemics decimated the population. Others died in Spanish owned gold mines.
In 1598 a party of warriors from Purén led by Pelantaro, who were returning south from a raid in Chillán area, ambushed Martín García Óñez de Loyola and his troops while they rested without taking any precautions against attack. Almost all the Spaniards died, save a cleric named Bartolomé Pérez, who was taken prisoner, and a soldier named Bernardo de Pereda. The Mapuche then initiated a general uprising which destroyed all the cities in their homeland south of the Biobío River.
In the years following the Battle of Curalaba a general uprising developed among the Mapuches and Huilliches. The Spanish cities of Angol, Imperial, Osorno, Santa Cruz de Oñez, Valdivia and Villarrica were either destroyed or abandoned. Only Chillán and Concepción resisted Mapuche sieges and raids. With the exception of the Chiloé Archipelago, all Chilean territory south of the BíoBío River was freed from Spanish rule. In this period the Mapuche Nation crossed the Andes Range to conquer the present Argentine provinces of Chubut, Neuquen, La Pampa and Río Negro. Spain never again attempted to retake those territories.
Incorporation into Chile and Argentina
In the 19th century Chile experienced a fast territorial expansion. Chile established a colony at the Strait of Magellan in 1843, settled Valdivia, Osorno and Llanquihue with German immigrants and conquered land from Peru and Bolivia. Later Chile would also annex Easter Island. In this context Araucanía began to be conquered by Chile due to two reasons. First, the Chilean state aimed for territorial continuity and second it remained the sole place for Chilean agriculture to expand.
Between 1861 and 1871 Chile incorporated several Mapuche territories in Araucanía. In January 1881, having decisively defeated Peru in the battles of Chorrillos and Miraflores, Chile resumed the conquest of Araucanía.
Historian Ward Churchill has claimed that the Mapuche population dropped from a total of half a million to 25,000 within a generation as result of the occupation and its associated famine and disease. The conquest of Araucanía caused numerous Mapuches to be displaced and forced to roam in search of shelter and food. Scholar Pablo Miramán claims the introduction of state education during the Occupation of Araucanía had detrimental effects on traditional Mapuche education.
In the years following the occupation the economy of Araucanía changed from being based on sheep and cattle herding to one based on agriculture and wood extraction. The loss of land by Mapuches following the occupation caused severe erosion since Mapuches continued to practice a massive livestock herding in limited areas.