The Spanish didn't defeat the Inca Empire at its height. They arrived after a smallpox epidemic killed the emperor and a subsequent brutal civil war between his sons shattered the empire. This left the civilization politically fractured and militarily exhausted, making it ripe for conquest by a small force.

Despite their aggressive plan, the psychological toll on the 168 Spaniards facing an army of thousands was immense. A firsthand account reveals their sheer terror, noting that many "urinate without noticing it out of pure terror" while waiting in hiding for the ambush to begin.

Facing mutiny, Francisco Pizarro drew a line in the sand, offering a stark choice between returning to poverty or pursuing riches through extreme hardship. This dramatic act served as a powerful filter, weeding out the uncommitted and forging an intensely loyal core group—the "Famous 13"—who would stick with him through anything.

The Spanish used a legal document called the "Requerimiento" to legitimize conquest. Before attacking, they read a history of the world and demanded submission to the Pope and Spanish King. Refusal provided a legal pretext for slaughter, a practice some Spaniards at the time considered absurd.

In a surreal display of dominance, Francisco Pizarro held a formal dinner with Atahualpa just hours after slaughtering thousands of his followers. He then had a mattress prepared for the Inca emperor to sleep beside him, a bizarre and intimate assertion of absolute control.

The famous moment where Atahualpa supposedly threw down a prayer book, sparking the massacre, was a manufactured pretext. The Spanish, already in ambush positions, simply needed a justification. The book ending up in the dust—whether thrown or dropped—provided the trigger for their pre-planned attack.

The historian Polybius described the Roman sack of New Carthage, noting the practice of killing indiscriminately—including cutting dogs in half—was a deliberate policy. This was not random brutality but a calculated psychological tactic to inspire terror and ensure swift surrenders in future conflicts.

To project absolute strength, Atahualpa engaged in psychological warfare against his own men. After he remained stoic as a Spanish horse breathed on him, he ordered the execution of soldiers (and their families) who had flinched, brutally enforcing a public code of fearlessness.

Francisco Pizarro's invasion of Peru was heavily influenced by the recent success of his cousin, Hernán Cortés, in Mexico. The fall of the Aztecs provided a tangible model for conquest, proving that small bands of conquistadors could topple vast empires. This precedent made it easier for Pizarro to secure funding and royal support.