A region of the Middle East known as the Fertile Crescent was a land of diverse peoples. Despite waves of invasion and conquest in the region, the successive empires advanced trade, created new methods of government, and carried out building projects. Many made lasting cultural and economic contributions to later civilizations. For example, the Phoenicians founded new settlements across the Mediterranean. Their cultural contributions include an alphabet that became a model for others in the region. The Aramaeans' language, Aramaic, became the primary language of trade. The Lydians initiated the use of coins as a medium of exchange, replacing barter. Monotheism-the belief of the Israelites in only one, all-powerful god-became the basis of Judaism, Christianity, and Islam.