The earliest mention of Babylon is in a dated tablet of the reign of Sargon of Akkad (24th century BCshort chr.). Over the years, its power and population waned. From around the 20th century BC, it was occupied by Amorites (nomadic Semitic tribes), fleeing southern Mesopotamia from the west. The First Babylonian Dynasty was established by Sumu-abum, but the city-state controlled little surrounding territory until it became the capital of Hammurabi's empire. Hammurabi is known for codifying the laws of Babylonia, that were to have a profound influence on the region. (ca. 18th century BC). From that time onward, it continued to be the capital of Babylonia, although during the 440 years of domination by the Kassites (1595–1185 BC), the city was renamed "Karanduniash".