<P> The word "census" originated in ancient Rome from the Latin word censere ("to estimate"). The census played a crucial role in the administration of the Roman Empire, as it was used to determine taxes . With few interruptions, it was usually carried out every five years . It provided a register of citizens and their property from which their duties and privileges could be listed . It is said to have been instituted by the Roman king Servius Tullius in the 6th century BC, at which time the number of arms - bearing citizens was supposedly counted at around 80,000 . The 6 BC "census of Quirinius" undertaken following the imposition of direct Roman rule in Judea was partially responsible for the development of the Zealot movement and several failed rebellions against Rome that ended in the Diaspora . The 15 - year indiction cycle established by Diocletian in AD 297 was based on quindecennial censuses and formed the basis for dating in late antiquity and under the Byzantine Empire . </P> <P> In the Middle Ages, the Caliphate began conducting regular censuses soon after its formation, beginning with the one ordered by the second Rashidun caliph, Umar . </P> <P> The Domesday Book was undertaken in AD 1086 by William I of England so that he could properly tax the land he had recently conquered in medieval Europe . In 1183, a census was taken of the crusader Kingdom of Jerusalem, to ascertain the number of men and amount of money that could possibly be raised against an invasion by Saladin, sultan of Egypt and Syria . </P> <P> In the 15th century, the Inca Empire had a unique way to record census information . The Incas did not have any written language but recorded information collected during censuses and other numeric information as well as non-numeric data on quipus, strings from llama or alpaca hair or cotton cords with numeric and other values encoded by knots in a base - 10 positional system . </P>

What is meant by census method in what conditions is this method used