Quipus, sometimes known as khipus or talking knots, were recording devices historically used in the region of Andean South America. A quipu usually consisted of colored, spun, and plied thread or strings made from cotton or camelid fiber. For the Inca, the system aided in collecting data and keeping records, ranging from monitoring tax obligations, properly collecting census records, calendrical information, and military organization. The cords contained numeric and other values encoded by knots in a base ten positional system. A quipu could have only a few or up to 2,000 cords. The configuration of the quipus have also been ""compared to string mops."" Archaeological evidence has also shown a use of finely carved wood as a supplemental, and perhaps more sturdy, base on which the color-coordinated cords would be attached. A relatively small number have survived.Objects that can be identified unambiguously as quipus first appear in the archaeological record in the first millennium CE. They subsequently played a key part in the administration of Tahuantinsuyu, the empire controlled by the Incan ethnic group, which flourished across the Andes from c. 1450 to 1532 CE. As the region was subsumed under the invading Spanish Empire, the use of the quipu faded from use, to be replaced by European writing systems. However, in several villages, quipu continued to be important items for the local community, albeit for ritual rather than recording use. It is unclear as to where and how many intact quipus still exist, as many have been stored away in mausoleums, 'along with the dead.'Quipu is the Spanish spelling and the most common spelling in English. Khipu (pronounced [ˈkʰipu]) is the word for ""knot"" in Cusco Quechua (the native Inca language); the kh is an aspirated k. In most Quechua varieties, the term is kipu.