Mesopotamian religion refers to the religious beliefs and practices followed by the Sumerian and East Semitic Akkadian, Assyrian, Babylonian and later migrant Arameans and Chaldeans, living in Mesopotamia (a region encompassing modern Iraq, southeast Turkey and northeast Syria) that dominated the region for a period of 4200 years from the fourth millennium BCE throughout Mesopotamia to approximately the 10th century CE in Assyria.