Kharaj

Kharaj was a land tax levied in Islamic states on agricultural land, originally applied to territory conquered by Muslim armies and worked by non-Muslim cultivators. It formed a key source of revenue for the Rashidun and Umayyad Caliphates, where disputes over its payment by converts became a source of social tension. The Sokoto Caliphate also drew on kharaj as part of its Islamic fiscal system.