In ancient Mesopotamia, specialization played a crucial role in the development of early settlements along the Tigris and Euphrates rivers. As people began to settle in one place, they no longer needed everyone to farm, allowing some individuals to focus on other tasks such as pottery, weaving, or metalworking. This division of labor led to more advanced societies. Additionally, as these settlements grew, powerful leaders emerged, often attempting to monopolize control over valuable resources like water and fertile land. To secure their dominance, some rulers engaged in military conquest, expanding their territories and demanding tribute from neighboring lands. Tributary systems allowed these rulers to grow wealthier without constant warfare, as smaller states offered goods and resources in exchange for protection or autonomy.