Only from the time that written documents are available do we know anything for certain about the movements of ethnic groups and language groups in Eurasia. For the preceding period, we have to be content with reconstructions on the basis of later situations and backward projection from there, in combination with archeological material that is not always straightforward in its significance. We call the people who created the first urban civilization in Mesopotamia Sumerians, for they themselves in their written documents call their land Sumer. Their language is not related to any other language known to us. In contrast, the land of Akkad (Agade) bordering Sumer to the north was inhabited from around 3000 BC by speakers of a Semitic language, Akkadian, who had adopted the script of their Sumerian neighbors. These Akkadians probably originated in the desert and semi-desert areas of Syria and northern Arabia, from where in the course of time various Semitic peoples, herdsmen in origin, would emerge and disperse all over the Near East. They constituted a single language family that in the preceding millennia had become separated from its near relative, the family of the Hamitic languages—to which the Egyptians and the Berber peoples of northern Africa belonged. The Semitic migrations began around 3000 BC with the settlement of Akkadians in Mesopotamia; later in the 3rd and 2nd millennia, there followed the Amorites, who likewise infiltrated in and settled all over Mesopotamia; in the later 2nd and early 1st millennium BC, it would be the Aramaeans who would penetrate into Mesopotamia, Syria, and Palestine.