Academics have not reached a consensus on the geographical boundaries of the Middle East. However, for the purposes of this chapter, this region will encompass the broadly defined areas known as Persia, Mesopotamia, the Levant, Asia Minor, and the Arabian Peninsula. The Middle East straddles three continents, including Asia, Africa, and Europe. The geography of the area promoted cultural diffusion by facilitating the spread of peoples, ideas, and goods along overland and maritime trade routes. In an area generally characterized by its aridity, climate has influenced settlement patterns. Larger settlements are found in river valleys and well-watered areas along the littoral. In these areas, we see the development and spread of productive agriculture.