Determination of Acre During the Timurid Period On the Basis of a Short Manuscript Containing Rules in Account Science and Area Measurement

Land tax had been one of the most important tax categories and one of the main income sources for Iranian governments during the Middle Ages; therefore, surveying cultivated lands attracted the special attention of  the rulers and court agents in that period. Since knowing the units of the survey and measuring the levels and area can increase one's understanding of each period's governmental and state affairs, the present study is initially to introduce a short manuscript containing rules in account science and area measurement firstly, a 15th century treatise on mathematics and geometric education, and then to answer following questions: "What were the units for measuring levels and determining the area during the Timurid period?", and, " What was the relationship between the selection of these measurement units and the Timurid bureaucracy?" And also, according to aforementioned manuscript information and on the basis of the metric measurement method, it has been tried in present study to determine the amount of "acre" and to prove that as a measurement unit it is independent of other variables, including the types of cultivating, irrigation and seed. The findings show that "the king acre" (Djarib-e-shahi) and "the peasant acre" (Djarib-e-dehqani) have been the general units used to survey area, and also other units such as "Dhira", "Qabda" and "Ashl", which were directly related to the Timurids ruling policy of uniformity of  length and weight units, were used in land surveying. They also show that the theories of scholars such as Lambton and Hinz that this unit were determined, in Timurid period, upon the types of land cultivation or irrigation are not acceptable.