Battle of Tucapel — Mapuche Kill Valdivia

Mapuche forces under the military genius Lautaro, who had served Valdivia as a groom and learned Spanish tactics and cavalry weaknesses, ambush and destroy Valdivia's force at Fort Tucapel on Christmas Day. Valdivia is captured and executed. Lautaro launches a general Mapuche uprising that nearly expels the Spanish from Chile entirely. He is killed in 1557 but the Araucanian War becomes one of the longest and most costly armed conflicts of colonial America, continuing for over 200 years. The Mapuche remain undefeated until the 1880s.