All non-nobles in the Inca empire had to perform the 'mita' service tax. This included labor on roads, bridges and in mines, runners on post roads, personal service for nobles, and other public work. It has been estimated that 30,000 men built the fortress of Sacsahuaman. Some districts of the empire provided special services and so were exempt from the mita. The Chicha people made special carved logs used for sacrificial fires, the Rucana people were used as litter-bearers and the Chumpivilca trained dancers for court. Craftsmen and skilled laborers were also exempt from the tax.
