Mesopotamian art developed in the area between the Tigris and Euphrates rivers from prehistory to the 6th century BC. Their art reflects both their love and fear of these natural forces, as well as their military conquests. The soil of Mesopotamia yielded the civilization’s major building material, i.e. mud brick, that was also used for their pottery, terra-cotta sculpture, and writing tablets. The art of Mesopotamia reveals a 4000-year tradition that appears, on the surface, homogeneous in style and iconography. It was created and sustained, however, by waves of invading peoples who differed ethnically and linguistically. Each of these groups made its own contribution to art until the Persian conquest of the 6th century BC. The first dominant people to control the region and shape its art were the non-Semitic Sumerians, followed by the Semitic Akkadians, Babylonians, and Assyrians. Control and artistic influences at times extended to the Syro-Palestinian coast, and techniques and motifs from outlying areas had an impact on Mesopotamian centers. As other peoples invaded the region, their art was shaped by native Mesopotamian traditions.