A panaca or panaqa, or panaka was a family clan of the Sapa Inca, the kuraka or emperor of the Inca Empire. The panakas were formed by the descendants of a Sapa Inca or his wife. The basic social institution of the Incas is the ayllu. An ayllu is a group of families that descended from a common ancestor, united by culture and religion, in addition to the agricultural work, livestock and fishing of the same territory. The ayllu concept transcended into nobility, so that the royal kinship could establish a lineage, called panaca or royal house.