The Spanish conquest of the Inca Empire, also known as the Conquest of Peru (), was one of the most important campaigns in the Spanish colonization of the Americas (the broader European colonization of the Americas). After years of preliminary exploration and military skirmishes, 168 Spanish soldiers under conquistador Francisco Pizarro, along with his brothers in arms and their Indian auxiliaries, captured the last Sapa Inca, Atahualpa, at the Battle of Cajamarca in 1532. It was the first step in a long campaign that took decades of fighting but ended in Spanish victory in 1572 and colonization of the region as the Viceroyalty of Peru. The conquest of the Inca Empire, led to spin-off campaigns into present-day Chile and Colombia, as well as expeditions to the Amazon Basin and the surrounding rainforest.

When the Spanish arrived at the borders of the Inca Empire in 1528, it spanned a considerable area and was by far the largest of the four grand pre-Columbian civilizations. Extending southward from the Ancomayo, which is now known as the Patía River, in southern present-day Colombia to the Maule River in what would later be known as Chile, and eastward from the Pacific Ocean to the edge of the Amazonian jungles, it covered some of the most mountainous terrains on Earth. In less than a century, the Inca had expanded their empire from about in 1448 to in 1528, just before the arrival of the Spanish. This vast area of land varied greatly in culture and climate. Because of the diverse cultures and geography, the Inca allowed many areas of the empire to be governed under the control of local leaders, who were watched and monitored by Inca officials. Under the administrative mechanisms established by the Inca, all parts of the empire answered to, and were ultimately under the direct control of, the Inca Emperor.Covey (2000). Scholars estimate that the population of the Inca Empire was between 12 and 16 million.Means (1932)."La catastrophe démographique" (The Demographic Catastrophe"), L'Histoire n°322, July–August 2007, p. 17.

Some scholars, such as Jared Diamond, believe that while the Spanish conquest was undoubtedly the proximate cause of the collapse of the Inca Empire, it may very well have been past its peak and already in the process of decline. In 1528, Emperor Huayna Capac ruled the Inca Empire. He could trace his lineage back to a "stranger king" named Manco Cápac, the mythical founder of the Inca clan, who, according to tradition, emerged from a cave in a region called Paqariq Tampu.

Huayna Capac was the son of the previous ruler, Túpac Inca, and the grandson of Pachacuti, the Emperor who, by conquest, had commenced the dramatic expansion of the Inca Empire from its cultural and traditional base in the area around Cusco. On his accession to the throne, Huayna Capac had continued the policy of expansion by conquest, taking Inca armies north into what is today Ecuador.Prescott, W.H., 2011, The History of the Conquest of Peru, Digireads.com Publishing, While he had to put down a number of rebellions during his reign, by the time of his death, his legitimacy was unquestioned, as was the primacy of Inca power.

Expansion had caused its own set of problems. Many parts of the empire retained distinct cultures, which were at best reluctant to become part of the greater imperial project. Due to its size, and the fact that all communication and travel had to take place by foot or by boat, the Inca Empire proved increasingly difficult to administer and govern, with the Inca Emperor having increasingly less influence over local areas.

Huayna Capac relied on his sons to support his reign. While he had many children, both legitimateborn of his sister-wives, under the Inca systemand illegitimate, two sons are historically important. Prince Túpac Cusi Hualpa, also known as Huáscar, was the son of Coya Mama Rahua Occllo of the royal line. The second was Atahualpa, an illegitimate son who was likely born of a daughter of the last independent King of Quitu, one of the states conquered by Huayna Capac during the expansion of the Inca Empire. These two sons would play pivotal roles in the final years of the Inca Empire.

The Spanish conquistador Pizarro and his army of men were greatly aided in their enterprise by invading when the Inca Empire was in the midst of a war of succession between the princes Huáscar and Atahualpa. Atahualpa seems to have spent more time with Huayna Capac during the years when he was in the north with the army conquering Ecuador. Atahualpa was thus closer to and had better relations with the army and its leading generals. When both Huayna Capac and his eldest son and designated heir, Ninan Cuyochic, died suddenly in 1528 from what was probably smallpox, a disease introduced by the Spanish into the Americas, the question of who would succeed as emperor was thrown open. Huayna had died before he could nominate the new heir.

At the time of Huayna Capac's death, Huáscar was in the capital Cuzco, while Atahualpa was in Quito with the main body of the Inca army. Huáscar had himself proclaimed Sapa Inca (i.e. "Only Emperor") in Cuzco, but the army declared loyalty to Atahualpa. The resulting dispute led to the Inca Civil War, prior to the conquest.

Chronology of the last years of the Inca Empire

c. 1528 – Francisco Pizarro and Diego de Almagro make first contact with the Inca Empire at Tumbes, the northernmost Inca stronghold along the coast. The Inca Emperor Huayna Capac died from European-introduced smallpox. Death sets off a civil war between his sons: Atahualpa and Huáscar 1528–1529 – Pizarro returns to Spain where the Queen of Spain grants him the license to conquer Peru 1531–1532 – Pizarro's third voyage to Peru. Spaniards form a bond with the Natives (Huancas, Chankas, Cañaris and Chachapoyas) who were under the oppression of the Inca Empire, and Pizarro includes them among his troops to face the Incas. Atahualpa is captured by Spanish. 1533 – Almagro arrives; Atahualpa is executed after he orders Huáscar to be killed; Pizarro subdues Cuzco and installs seventeen-year-old Manco Inca as new Inca Emperor 1535 – Pizarro founds the city of Lima; De Almagro leaves for present-day Chile 1536 – Gonzalo Pizarro steals Manco Inca's wife, Cura Olcollo. Manco rebels and surrounds Cuzco. Juan Pizarro is killed, and Inca general Quizo Yupanqui attacks Lima 1537 – Almagro seizes Cuzco from Hernando and Gonzalo Pizarro. Rodrigo Orgóñez sacks Vitcos and captures Manco Inca's son, Titu Cusi. Manco escapes and flees to Vilcabamba, which became the capital of the Neo-Inca State 1538 – Hernando Pizarro executes Diego de Almagro 1539 – Gonzalo Pizarro invades and sacks Vilcabamba; Manco Inca escapes but Francisco Pizarro executes Manco's wife, Cura Olcollo 1541 – Francisco Pizarro is murdered by Diego de Almagro II and other supporters of De Almagro 1544 – Manco Inca is murdered by supporters of Diego de Almagro. The Inca do not stop their revolt 1572 – Viceroy of Peru, Francisco Toledo, declares war on the Neo-Inca State; Vilcabamba is sacked and Túpac Amaru, the last Inca Emperor, is captured and executed in Cuzco. The Neo-Inca capital of Vilcabamba is abandoned; the Spanish remove inhabitants and relocate them to the newly established Christian town of San Francisco de la Victoria de Vilcabamba.MacQuarrie (2007)

Beginning of the conflict The civil war between Atahualpa and Huascar weakened the empire immediately prior to its struggle with the Spanish. Historians are unsure if a united Inca Empire would have defeated the Spanish in the long term due to factors such as the high mortality from disease and the resulting social disruption, and the superior military technology of the conquistadors, who possessed horses, dogs, metal armor, swords, cannons, and primitive, but effective, firearms.Kubler (1945). Atahualpa appeared to be more popular with the people than his brother, and he was certainly more valued by the army, the core of which was based in the recently conquered northern province of Quito.

At the outset of the conflict, each brother controlled his respective domains, with Atahualpa secure in the north, and Huáscar controlling the capital of Cuzco and the large territory to the south, including the area around Lake Titicaca. This region had supplied large numbers of soldiers for Huáscar's forces. After a period of diplomatic posturing and jockeying for position, open warfare broke out. Huáscar seemed poised to bring the war to a rapid and decisive conclusion, as troops loyal to him took Atahualpa prisoner, while he was attending a festival in the city of Tumebamba. However, Atahualpa quickly escaped and returned to Quito. There, he was able to amass what is estimated to be at least 30,000 well-trained soldiers. While Huáscar managed to muster about the same number of soldiers, they were much less experienced.

Atahualpa sent his forces south under the command of two of his leading generals, Challcuchima and Quisquis, who won an uninterrupted series of victories against Huáscar that soon brought them to the very gates of Cuzco. On the first day of the battle for Cuzco, the forces loyal to Huáscar gained an early advantage. However, on the second day, Huáscar personally led an ill-advised "surprise" attack, of which the generals Challcuchima and Quisquis had advanced knowledge. In the ensuing battle, Huáscar was captured, and resistance completely collapsed. The victorious generals sent word north by chasqui messenger to Atahualpa, who had moved south from Quito to the royal resort springs outside Cajamarca. The messenger arrived with news of the final victory on the same day that Pizarro and his small band of adventurers, together with some Indian auxiliaries, descended from the Andes into the town of Cajamarca.

Arrival of Pizarro

Francisco Pizarro and his brothers (Gonzalo, Juan, and Hernando) were attracted by the rumors of a rich and fabulous kingdom. They had left the then-impoverished Extremadura, like many settlers after them.

In 1529, Francisco Pizarro obtained permission from the Spanish Monarchy to conquer the land they called Peru.

According to historian Raúl Porras Barrenechea, Peru is not a Quechuan or Caribbean word, but a Indo-European or hybrid word. Unknown to Pizarro, as he was lobbying for permission to mount an expedition, his proposed enemy was being devastated by the diseases brought to the American continents during earlier Spanish contacts.

When Pizarro arrived in Peru in 1532, he found it vastly different from when he had been there just five years before. Amid the ruins of the city of Tumbes, he tried to piece together the situation before him. From two local boys, whom Pizarro had taught how to speak Spanish in order to translate for him, Pizarro learned of the civil war and of the disease that was destroying the Inca Empire.

After four long expeditions, Pizarro established the first Spanish settlement in northern Peru, calling it San Miguel de Piura.

When first spotted by the American Indians, Conquistador Pizarro and his men were thought to be Viracocha Cuna or "gods". The Indians described Pizarro's men to the Inca. They said that capito was tall with a full beard and was completely wrapped in clothing. The Indians described the men's swords and how they killed sheep with them. The men did not eat human flesh, but rather sheep, lamb, duck, pigeons, and deer, and cooked the meat. Atahualpa was fearful of what the newly arrived white men were capable of. If they were runa quicachac or "destroyers of peoples", then he should flee. If they were Viracocha Cuna Runa allichac or "gods who are benefactors of the people", then he should not flee, but welcome them. The messengers went back to Tangarala, and Atahualpa sent Cinquinchara, an Orejon warrior, to the Spanish to serve as an interpreter.