Zanj Rebellion
Since the time of the Sumer, agriculture in Mesopotamia involved major melioration, including drainage and building of irrigation canals. After the collapse of the Mesopotamian civilization and the Arab conquest the territory was derelict, which resulted in the restoration of the original wetland conditions. The wetlands were gradually populated by the Marsh Arabs, or Ma'dan, who grew rice and grazed buffalo on the natural vegetation. At times, the marshes have also served as a refuge for escaped slaves and serfs, such as during the Zanj Rebellion.