The most frequently asked question is how 150 to 180 Spaniards were able to easily overcome the Inca empire, containing between 12 and 16 million inhabitants. We now know that this was not a result of their military power and superior knowledge; it was simply due to the fact that when the Spaniards arrived, the Incas were in the middle of a bloody civil war.

Cusco was always the capital of Tahuantinsuyo. Its legitimate monarch was Tupac Kusi Wallpaq, who was also known as Waskar or Huascar. He had a brother called Atahualpa, who usurped the throne of Tumipampa, today the Basin of Ecuador, where he was crowned as the new Inca. Atahualpa and
Huascar fought some terrible battles, and this was the situation when the Spaniards arrived on the Peruvian coast and entered the city of Cajamarca in November.

The Spaniards captured Atahualpa, who from his imprisonment asked them to murder Huascar and all the Cusco nobles, or "orejones".

When the Spaniards learned about these events, they blamed Atahualpa for them, decreeing his death sentence. After this murder, the Spaniards made their way to Cusco, where they expected an enthusiastic welcome, as they had eliminated the traitor to the true Inca. They were accepted by the nobility and welcomed to the capital of the empire by the nobles.
They were shown round all the fine buildings by its inhabitants: palaces, temples, and towns and cities, but nothing was said about Machu Picchu as it was a very special and hidden place; besides, it was already lost to memory. Thus the Spaniards never learned about or went to Machu Picchu.

On November 15, 1532 the Spaniards, armed with horses and cannon managed to end the reign of Tahuantinsuyo. On that day, Inca Atahualpa was ambushed and captured by the Spaniards in the plaza of Cajamarca. The demigod was whipped before the crowd, while the sacred mascapaicha tumbled to the ground. When he finally died, between June 28 and July 29, 1533, the political cohesion of Tahuantinsuyo had already been destroyed.

This "feat" is explained mostly by the fact that the Spaniards had help from Huascar's supporters and many regional sectors, all of them possessing thousands of warriors, tired of Inca domination.