Civil war left the Inca Empire open to 168 Spaniards
In 1532 Francisco Pizarro’s 168 soldiers seized Sapa Inca Atahualpa at Cajamarca—the opening move of a campaign that ended Inca sovereignty by 1572 as the Viceroyalty of Peru. Smallpox and a Huáscar–Atahualpa succession war had already torn the Andes’ largest state.
By 1528 the Inca realm ran from southern Colombia’s Patía (Ancomayo) region to Chile’s Maule River and inland toward Amazonia—roughly 1.8 million square kilometers, up from about 400,000 in 1448, with perhaps twelve to sixteen million people. Local leaders governed under Inca oversight across wildly varied cultures. Huayna Capac, heir of Túpac Inca and grandson of expansionist Pachacuti, pushed north into Ecuador before he and designated heir Ninan Cuyochic died suddenly in 1528, likely of smallpox introduced via earlier Spanish contacts.
Legitimate prince Huáscar in Cuzco and Quito-based Atahualpa, favored by the northern army, fought a civil war. Atahualpa escaped early capture, raised perhaps thirty thousand seasoned troops against similarly sized but greener Huáscar forces, and through generals Challcuchima and Quisquis took Cuzco. Victory news reached Atahualpa at Cajamarca the same day Pizarro’s band descended from the Andes. Pizarro, from impoverished Extremadura with brothers Gonzalo, Juan, and Hernando, had royal leave in 1529 to conquer “Peru”; returning in 1532 he found Tumbes ruined and learned of plague and civil war through boy interpreters.
Indigenous auxiliaries were decisive: Huanca seeking revenge, Cañari under Vilchumlay after Atahualpa’s devastations, and Chachapoyas chasing independence stiffened Spanish ranks, including the push on Cuzco. Atahualpa’s agent Cinquinchara judged the strangers men, not gods—about 170–180 strong—and urged killing them. Pizarro reached Cajamarca on 15 November 1532 while Atahualpa fasted at nearby baths after Huáscar’s capture. Decades of fighting followed before Spanish victory in 1572, spinning campaigns into Chile, Colombia, and Amazonia.
Jared Diamond and others treat Spanish arrival as proximate cause atop an empire already strained by scale, reluctant provinces, and foot-only communications—collapse accelerated, not invented, at Cajamarca.
Source: Spanish conquest of the Inca Empire
