The Mapuche are the largest Indigenous group in South America, occupying regions of the central valley of Chile, and parts of westcentral Argentina. Prior to Spanish arrival, the Mapuche lived in scattered farming villages throughout the Central Valley, with each settlement having its own chief. During a 350 year long struggle against the Spanish beginning in the 16th century, the Mapuche reorganized their traditional way of life with villages forming military, political, and economic alliances.