 Spanish Conquistadors, operating privately, deposed the Aztec, Inca and Maya governments with extensive help from local factions and took control of vast stretches of land.This New World empire was at first a disappointment, as the natives had little to trade.Diseases such as smallpox and measles that arrived with the colonizers devastated the native populations, especially in the densely populated regions of the Aztec, Maya and Inca civilizations, and this reduced the economic potential of conquered areas.