Market Tax in Muslim Caliph's Era

After the formation of Islamic government by holy prophet، muhamad (pbuh)، and the caliphs’ governance، Islamic countries sometimes confronted with an increasing or decreasing in incomes، and meet with some unpredictable expenses. Gaining new economical sources they think about new solutions to reduce these expenses. One of these proposed solutions was market tax that was welcomed. This kind of tax that existed in former states too، in the Umayyad dynasty and Abbasid caliphate has been executed by a special method. Here we try to explain features and reasons of those circumstances and their consequences، by referring to historical data specially that which is relevant to that era.