Why were the Aztecs and Incas so easily defeated by smaller Spanish forces?

The Spanish forces although smaller had guns armor and horses while the native people had primitive spears and bows.

Answer: A civil war

Explanation:The Spanish explorer Francisco Pizarro invaded the Incan Empire in 1532, seeking riches. The Inca had already had some contact with Europeans, and many had died of European diseases. The empire was also weakened by a civil war between two ruling brothers. Pizarro manipulated the two sides, eventually defeating both.