Prior to European colonization, the Andean region of Bolivia was a part of the Inca Empire – the largest state in Pre-Columbian America. The conquistadors took control of the region in the 16th century. During most of the Spanish colonial period, this territory was known as Upper Peru and was under the administration of the Viceroyalty of Peru, which included most of Spain's South American colonies, although the area enjoyed substantial autonomy under the jurisdiction of the Royal Court of Charcas. After declaring independence in 1809, 16 years of war followed before the establishment of the Republic, named for Simón Bolívar, on August 6, 1825.