Before Spanish colonization, the Andean region of Bolivia was part of the Inca Empire, while the northern and eastern lowlands were inhabited by independent tribes. Spanish ''conquistadors'' arriving from Cusco and Asunción took control of the region in the 16th century. During the Spanish colonial period Bolivia was administered by the Real Audiencia of Charcas. Spain built its empire in large part upon the silver that was extracted from Bolivia's mines.