The Battle of (or Massacre at) Cajamarca was a surprise attack on the Inca royal entourage orchestrated by Francisco Pizarro. Sprung on the evening of November 16, 1532 in the great plaza of Cajamarca, the ambush claimed the lives of thousands of Incas and achieved the goal of capturing Emperor Atahualpa.
The confrontation at Cajamarca was the culmination of a months-long struggle involving espionage, subterfuge, and diplomacy between Pizarro and the Inca via their respective envoys. Atahualpa had received the invaders from a position of immense strength. Encamped along the heights of Cajamarca with legions of battle-tested troops fresh from their victories in the civil war against his half-brother Huascar, the Inca felt they had little to fear from Pizarro's tiny army, however exotic its dress and weaponry. In a calculated show of goodwill, Atahualpa had lured the adventurers deep into the heart of his mountain empire where any potential threat could be met with a show of force. Pizarro and his men arrived on November 15.
Atahualpa, unlike Moctezuma in Mexico, knew right away that these men were not gods nor were they representatives of the gods. The reports from his own spies confirmed that. According to Spanish sources, he planned to recruit a few of the conquistadores into his own service and to appropriate Spanish firearms and horses for his armies. He would then execute the others at his leisure.
The book History Of The Conquest Of Peru, written by 19th century author William H. Prescott, recounts the dilemma the Spanish force found itself in. Any assault on the Inca armies overlooking the valley would have been suicidal. Retreat was equally out of the question, because any show of weakness might have undermined their air of invincibility, and would invite pursuit and closure of the mountain passes. Once the great stone fortresses dotting their route of escape were garrisoned, argued Pizarro, they would prove impregnable. But to do nothing, he added, was no better since prolonged contact with the natives would erode the fears of Spanish supernaturality that kept them at bay. Unlike his kinsman Hernán Cortés, whom Pizarro emulated and who could call on Spanish reinforcements 200 miles away in Veracruz, Pizarro's nearest Spanish reinforcements were 2,000 miles away in Panama.
Pizarro gathered his officers on the evening of November 15th and outlined a scheme that recalled memories of Cortés' exploits in Mexico in its audacity: he would capture the emperor from within the midst of his own armies. Since this could not realistically be accomplished in an open field, Pizarro invited the Inca to Cajamarca. According to the chroniclers, no one slept that night and some even "wet themselves in their terror".
Atahualpa accepted this invitation. Leading a procession of over eighty thousand men, he advanced down the hillside very slowly the next day. Pizarro's fortunes changed dramatically in the late afternoon when Atahualpa announced that the greater part of his host would set up camp outside the walls of the city. He requested that accommodations be provided only for himself and his retinue, which would forsake its weapons in a sign of amity and absolute confidence.
Having concealed themselves within the city, the Spaniards allowed the Incas to enter unopposed. An incident occurred when Friar Vincente de Valverde approached the Inca and ordered him to renounce his pagan religion and to accept Catholicism as his faith and Charles V, the Holy Roman Emperor as sovereign. Atahualpa was equally insulted and confused by the Spaniard's demands. Although Atahualpa likely had no intention of conceding to their demands, according to chronicler Garcilaso de la Vega he did attempt inquiry into the Spaniard's faith and their king, but Pizarro's men began to grow impatient. The climax occurred when Atahualpa asked to see a Bible when Friar Valverde said it "spoke to him". Unfamiliar with how to open a book, the emperor became enraged when the friar tried to help him, and struck his arm. Then he opened it, but was unimpressed with the pages and words and threw the book to the ground. Historical accounts differ on whether the friar returned to Pizarro and related the incident, along with some demands by the emperor, after which Pizarro ordered the attack to begin, or if he immediately turned to the hidden Spanish troops and exhorted them to attack in the name of the Church, absolving them of the murders to come.
At the signal to attack, the Spaniards unleashed murderous gunfire at the vulnerable mass of Incas and surged forward in a concerted action. The effect was devastating: the shocked Incas offered such feeble resistance that the battle has often been labeled a massacre. Contemporary accounts by members of Pizzaro's force explain how the Spanish forces used a cavalry charge against the Inca forces, who had never seen horses, in combination with gunfire from cover (the Inca forces also had never encountered guns before). Other factors in the Spaniard's favor were their steel swords, helmets and armor, against the Inca forces which only had leather armor and were unarmed. The Spanish also had a few small cannon which were used to great effect in the crowded town square. The first target of the Spanish attack was the Inca Emperor and his top commanders; once these had been killed or captured the Inca forces were disorganized as the command structure of the army had been effectively decapitated.