Two years later, Babylon produced another rebel leader, Shamash-eriba. Beginning in the summer of 482 BC, Shamash-eriba seized Babylon itself and other nearby cities, such as Borsippa and Dilbat, and was only defeated in March 481 BC after a lengthy siege of Babylon. The precise cause of the unrest in Babylon is uncertain. It may have been due to tax increase. Prior to these revolts, Babylon had occupied a special position within the Achaemenid Empire, the Achaemenid kings had been titled as "King of Babylon" and "King of the Lands", perceiving Babylonia as a somewhat separate entity within their empire, united with their own kingdom in a personal union. Xerxes dropped "King of Babylon" from his titulature and divided the previously large Babylonian satrapy (accounting for most of the Neo-Babylonian Empire's territory) into smaller sub-units.