in 1536.Diseases brought by the Spanish reduced the Mapuche population by up to 80% as it fell from around 1 million to 150,000. The Spanish believed by the 1590s that they were about to win the war.

Over 3,000 Mapuche were killed at the Battle of Andalien and it was one of the last battles in which they fought the Spanish using conventional tactics. As the war progressed the Mapuche turned to insurgency tactics.