Answer:
In 1532, the Inca Empire fell to a Spanish force of only 168 men and 62 horses. Francisco Pizarro and his conquistadors crushed one of the world's mightiest empires without a single Spanish casualty. Pizarro had cannons, gunpowder and armor, but the Incas vastly outnumbered his small army.
which is The Inca fell by a combination of civil war and the Spanish invasion. Hope this help