Origins
The Inca people emerged as a small Quechua-speaking polity in the southern Peruvian Andes in the 12th or 13th century, with their political-religious centre at Cuzco in the upper Vilcanota valley. The transition from regional polity to imperial state is conventionally dated to the reign of the Inca emperor Pachacuti (reigned 1438–1471), who expanded Cuzco’s military and political control northward and southward along the Andean cordillera through approximately three decades of sustained military campaigning.
The empire’s indigenous name was Tawantinsuyu — “the four regions together,” referring to the four administrative quadrants (suyus) that radiated from Cuzco. The four quadrants — Chinchaysuyu (north), Antisuyu (east, into the Amazon basin), Cuntisuyu (west, the coast), and Collasuyu (south, into modern Bolivia and Chile) — were governed by hereditary local elites under Cuzco-appointed Inca administrators.
The imperial system
The Inca Empire was the most administratively centralized state in pre-Columbian America. It was held together by several distinctive institutional features:
The road network — approximately 40,000 kilometres of paved imperial roads, with way-stations (tambos) at standardized intervals, connecting Cuzco to every major regional administrative centre. The road system was used by relay runners (chasquis) who could carry messages across the empire faster than any horse-borne courier system in pre-modern history.
The agricultural-storage system — extensive state-built terraced agriculture (the surviving terraces at sites like Machu Picchu and Pisac are the visible monuments) supplied state granaries (qollqa) that buffered regional food supplies against bad harvest years and supported military campaigns.
The labour-tribute system — the mit’a system organized periodic mandatory labour service by every adult male in the empire for state agricultural, construction, military, and mining projects. The system was inherited and adapted by Spanish colonial administration after 1532 and persisted in modified forms into the 19th century.
The administrative recording system — the khipu, a system of knotted cords used by trained imperial recorders to maintain administrative accounts of population, tribute, agricultural production, and military forces. The Inca had no writing system in the European sense; the khipu were the functional substitute. Modern scholarship has decoded the numerical content of khipu but has not (yet) been able to read the more elaborate khipu that contained narrative content.
The state religion — sun-worship centred on the temple of Coricancha in Cuzco. The Inca emperor was theoretically the son of the sun god Inti. The religious-political system was capable of being syncretized with local indigenous religious traditions across the empire’s wide territorial extent.
The empire reached its territorial maximum under Huayna Capac (reigned c. 1493–1527), extending from modern southern Colombia to the Maule River in central Chile — approximately 4,300 kilometres of north-south extent. The total population at peak is estimated at approximately 10–12 million.
The civil war and the Spanish conquest
Huayna Capac and his designated successor both died in approximately 1527 — almost certainly of a smallpox epidemic that had crossed the Andes from the Caribbean ahead of the actual Spanish military presence. The succession passed to two half-brothers, Huáscar (legitimate son ruling from Cuzco) and Atahualpa (the older bastard son commanding the Inca army in the north).
The succession civil war (1529–1532) was won by Atahualpa, whose general Quizquiz captured Huáscar in early 1532. The civil war had left the empire militarily exhausted, administratively fragmented, and politically polarized between Cuzco loyalists and Atahualpa’s northern army.
Francisco Pizarro landed on the northern Peruvian coast in early 1532 with 168 Spaniards (including 62 horsemen), one priest, and three cannons. He proceeded inland to Cajamarca, where Atahualpa was camped with his victorious army of approximately 80,000 troops. The two forces met on 16 November 1532. Pizarro’s force ambushed and captured Atahualpa in a single-afternoon engagement that killed approximately 7,000 Inca and no Spaniards.
Atahualpa offered a ransom of one room filled with gold and two rooms filled with silver — approximately 6 tonnes of gold and 11 tonnes of silver, delivered over the following nine months. Pizarro accepted the ransom, distributed it among his men, and then ordered Atahualpa’s execution on 26 July 1533, after a brief trial on charges including idolatry and Huáscar’s earlier murder.
The Spanish entered Cuzco on 15 November 1533. The empire’s institutional structure collapsed over the following decade as the Spanish installed puppet Inca rulers (Manco Inca, Sayri Tupac, Titu Cusi), suppressed several Indigenous uprisings, and progressively consolidated control of the Andean territories. The last independent Inca resistance, at the jungle redoubt of Vilcabambá under Tupac Amaru, fell in 1572. Tupac Amaru was beheaded in Cuzco on 24 September 1572. The Inca dynasty was over.
Consequences
The Spanish colonial administration of Peru — formalized as the Viceroyalty of Peru in 1542 — inherited the Inca administrative network, the road system, the mit’a labour tax, and the silver mining infrastructure. The vast silver deposits of Potosí (modern Bolivia), worked under the mit’a system by indigenous forced labour from 1545 onward, would supply approximately half of the world’s silver production for the following two centuries and finance the Spanish Empire’s European wars.
The Inca population collapsed by approximately 90% over the following century, primarily from smallpox, measles, typhus, and influenza. The Quechua language continues to be spoken by approximately 7–8 million people across the Andean region. The Inca site of Machu Picchu, a 15th-century royal estate above the Urubamba valley, was rediscovered by the American academic Hiram Bingham in 1911 and is now the most-visited archaeological site in South America.
The 18th-century Andean rebellion of Tupac Amaru II (1780–1783) — claiming descent from the last Inca emperor — was the largest indigenous uprising against Spanish colonial rule and a precursor to the early-19th-century Latin American independence movements.