Centered at Cuzco, Peru, the empire at the time of the Spanish conquest (1532) dominated the entire Andean area from Quito, Ecuador, S to the Río Maule, Chile, extending some 2,000 mi (3,200 km). Although the Inca showed a genius for organization, their conquests were facilitated by the highly developed social systems of some of the kingdoms that they absorbed, such as the Chimu, and the established agrarian communities that covered the area of their conquest. The Inca empire was a closely knit state. At the top was the emperor, an absolute monarch ruling by divine right. Merciless toward its enemies and requiring an obedience close to slavery, the imperial government was responsible for the welfare of its subjects. Everything was owned by the state except houses, movable household goods, and some individually held lands. In addition to cultivating the land, the common people were drafted to work on state projects such as mining, public works, and army service. This obligation was known as mita. From well-stocked storehouses were drawn goods to support priests, government servants, special artisans, the aged and the sick, and widows.
The royal family formed an educated, governing upper nobility, which at the time of the Spanish conquest numbered around 500. To further increase government control over an empire grown unwieldy, all who spoke Quechua became an "Inca class" by privilege and became colonists. Lesser administrative officials, formerly independent rulers, and their descendants were the minor nobility, or curaca class, also supported by the government.
For purposes of administration the empire was divided into four parts, the lines of which met at Cuzco; the quarters were divided into provinces, usually on the basis of former independent divisions. These in turn were customarily split into an upper and a lower moiety; the moieties were subdivided into ayllus, or local communities. Much as it exists today as the basic unit of communal indigenous society, so the ancient ayllu was the political and social foundation of Inca government. When a territory was conquered, surveys, consisting of relief models of topographical and population features, and a census of the population were made. With these reports, recorded on quipus, of the material and human resources in each province, populations were reshuffled as needed. Thus transplanted, and dominated by Quechua colonists, the subject peoples had less chance to revolt, and the separate languages and cultures were molded to the Inca pattern.
Religion, controlled by a hierarchy similar to the government hierarchy, emphasized ritual and organization. Heading the Inca gods was Viracocha. His servants were the sun, the god of the weather or thunder, the moon, the stars, the earth, and the sea. The sun god was foremost among these. Divination, sacrifices (human only at times of crisis), celebrations and ceremonies, ritual, feasts, and fasts were all part of Inca religion.