Mesopotamia has been conquered many times by many different people. It was the heartland of the Sumerian, Akkadian, Babylonian and Assyrian empires. As each new group moved into the region they adopted some of the culture, traditions, and beliefs of the people who had come before. It was conquered by Alexander the Great (332 BC), the Parthians (150 BC), the Romans, the Persian Empire, and the Arabs (7th century). It is still one of the most fertile (and therefore valuable) parts of the Middle East.