The Incas

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.

For more information see: http://www.nativeamericans.com/Incas.htm