The vast Inca empire, with its advanced culture and powerful armies, spanned most of the Andes along South America\'s western coast at the time of Spanish conquest in the early 16th century. The Incas had a very clear social structure. The ruler, Sapa Inca, and his wives, the Coyas, had supreme control over the empire. The High Priest and the Army Commander in Chief were next. Then came the Four Apus, the regional army commanders. Next came temple priests, architects, administrators and army generals. Next were artisans, musicians, army captains and the quipucamayoc, the Incan accountants. At the bottom were sorcerers, farmers, herding families and conscripts. WHO THE INCAS WERE The 16th-century written accounts of the Incas do not provide a very complete understanding of the economic and political organization of their state. It is clear, however, that the principles of Inca economics and politics were taken from old Andean traditions and were very different from European ones. The Inca state was not under the absolute control of its ruler. It was an array of dozens, if not hundreds, of different political, ethnic, and even linguistic groups. In order to maintain unity within the empire, an attempt was made to introduce uniform organizational and administrative procedures to the realm. This process, however, was far from complete in 1532, and administrative practices varied greatly from one part of the empire to another. An unusual characteristic of the Inca state was its ability to move people about the empire as colonists far from their homes. This custom of internal colonization allowed the Incas to place loyal groups in regions that were difficult to control. The practice also appears to have had economic aims in some cases; people could be relocated to develop new lands, new mines, or other