The Inca civil war of 1527–1532 — the dynastic conflict between the half-brothers Huáscar Inca and Atahualpa Inca over the succession to their father Huayna Capac — was, by aggregate casualties and political damage, the most destructive single event in pre-conquest Inca history. The war exhausted the imperial army and the empire's regional power balances on the very eve of the Spanish arrival. The contemporaneous coincidence of the civil war with the Spanish expedition of 1531-1532 is the principal reason for the apparently rapid collapse of the empire in the conquest: the empire did not, in any meaningful sense, collapse from a position of strength.
The succession question
Huayna Capac died around 1525 to 1527 (the dates are uncertain; the most widely accepted estimate is 1527) of an epidemic disease that the chronicles describe in terms consistent with smallpox. Smallpox is not known in the Andean disease ecology before the European arrival. The smallpox virus had been introduced to the Caribbean by the Spanish settlements after 1492 and had moved south through indigenous American population networks ahead of Spanish exploration. By the mid-1520s it had reached the northern Andes — well before any Spaniard set foot in Inca territory. The pandemic killed perhaps a third to half of the indigenous population of the affected regions in its first passage. Huayna Capac was among its victims; so was his designated successor, Ninan Cuyuchi; so were several other senior members of the imperial family. The disease, in this respect, did the substantive demographic work of the Spanish conquest before the Spanish conquerors arrived.
The succession went, on the basis of the surviving claimants and the support of the senior Cuzco lineages, to Huáscar — Huayna Capac's son by his principal wife Rahua Ocllo, born and raised in Cuzco. Huáscar was crowned at Cuzco with the support of the Cuzco-based panaqas of the previous Sapa Incas. The decision was not immediately contested.
The challenge came from the north. Atahualpa — Huayna Capac's son by a secondary wife (probably a daughter of the conquered Quitu royal family, though the chronicle accounts vary) — had been brought up at Quito and had served as his father's principal lieutenant in the northern provinces during the campaigns of the 1510s and 1520s. He commanded the loyalty of the bulk of the empire's experienced field army (the so-called Northern Army), based at Quito under the senior generals Quizquiz, Chalcuchimac, and Rumiñawi. When Huáscar's coronation was announced, Atahualpa did not accept the legitimacy of the decision. He claimed his father had divided the empire between them on his deathbed (an account disputed by the Cuzco-based historians), with the northern territories from Tomebamba (modern Cuenca, Ecuador) northward as a separate kingdom under his rule. Huáscar refused to accept the partition.
The campaigns
The civil war ran from approximately 1529 to 1532 in a sequence of escalating campaigns. The decisive military fact was that Atahualpa's Northern Army — the bulk of the imperial professional military, with experienced senior commanders — was substantially better than the army Huáscar could raise from Cuzco. Huáscar's forces were, in many cases, recently mobilised provincial levies under inexperienced senior commanders; the Cuzco military aristocracy had been politically displaced under Huáscar by his personal favourites, leading to defections to Atahualpa's cause among the senior officers.
The major engagements of the war were fought in the central highlands between Quito and Cuzco. The northern army under Quizquiz and Chalcuchimac, supplemented by reinforcements led by Atahualpa himself, advanced southward in a sequence of campaigns. The principal battles included Mochacaxa (an early Atahualpa victory in the Ecuadorian highlands), Ambato, and Chillopampa. The decisive engagement was at Quipaipan, near Cuzco, in early 1532, where Quizquiz and Chalcuchimac decisively defeated Huáscar's main army. Huáscar himself was captured. Atahualpa's generals entered Cuzco, executed substantial portions of the Cuzco-based imperial aristocracy who had supported Huáscar (the Spanish chronicler Sarmiento records mass killings of members of certain panaqas), and held the capital under occupation. Atahualpa himself, with a substantial bodyguard, was at Cajamarca in the northern highlands, en route from Quito to Cuzco for his formal coronation, when news reached him of strange foreign visitors who had landed on the coast and were marching inland to meet him.
The state of the empire
The empire that the Spanish expedition encountered in November 1532 was, in this context, very different from the empire that Huayna Capac had ruled five years earlier. Smallpox had killed perhaps a third of the population, including most of the senior leadership. The civil war had left tens of thousands of soldiers dead and many regional populations resentful of the Quito faction's victory. The Cuzco-based imperial aristocracy was substantially destroyed. Many subject populations — particularly those most recently conquered, like the Cañari in southern Ecuador, who had been brutally repressed by Atahualpa during the war — were ready to ally with any external power that promised relief from the new Quito-faction rulers. The administrative system was, in the strict sense, still operating; the road network, the storehouse system, the chasqui couriers, and the local kurakas were all functioning. But the political coherence of the imperial state was gone.
The Spanish expedition that arrived at the coastal site of Tumbes in 1531 and entered the highlands in 1532 had, in this sense, an opportunity that no comparable European expedition would ever again find in any other major non-European state. The Inca empire's collapse was not merely military: it was political, demographic, and dynastic. The story of how Pizarro's 168 men exploited the situation is the subject of the next chapter, and is one of the most consequential single episodes of the early modern period.
Atahualpa, at Cajamarca in the autumn of 1532, did not yet know that the visitors were going to alter the entire political situation of the Andean world. He treated them, on the limited information he had, as a curiosity. The decision to receive them peacefully — rather than to despatch them as he could easily have done — is the principal Atahualpa decision that contemporary historians have struggled to explain. It is the decision the next chapter takes as its starting point.
End of Chapter VI