4.6 First millennium BC
By the first millennium B.C.the world changed. This change was most palpable at the level of political power. Lacking definite physical boundaries, Mesopotamia was exposed to the risk of foreign invasion.  It suffered a significant intrusion in the third millennium B.C., and matters were much worse in the second. Sometimes the intruders were the hill tribes of western Iran, such as the Gutians of the third millennium and the Kassites of the second. Sometimes they were the pastoralists of the southern Near East, such as with the Amorites around 2000 B.C. and the Arameans a millennium later. But something all these invasions, large and small, had in common was that the newcomers as yet posed no threat to the cultural continuity of Mesopotamian civilization. The Amorites, for example, are described as a people who dwell in tents and have no knowledge of houses or grain. If such people successfully established their power in Mesopotamia, they soon found that they needed the appurtenances of civilization; and since they lacked their own, they adopted that of their subjects.
In the first millennium B.C. it might have seemed as if the pattern would continue as before. In the sixth century Mesopotamia was again invaded from Iran, this time by the Persians, who went on to devise a cuneiform script for their own language, and to use it in their royal inscriptions. But there was a difference. Mesopotamia was now only one of several cultural provinces of a very large Persian empire. In the fourth century the Greeks overthrew the Persians, and this time the invaders brought with them an urban civilization of their own.
Unlike neighboring Egypt and Mesopotamia, Syria was neither embellished nor weighed down by a third-millennium cultural tradition. Instead, the keynote of Syrian cultural history was instability and innovation. In the third millennium Ebla shows us a typical local adoption of the Sumerian literary tradition. Yet by the middle of the second millennium Syria had broken with the cumbersome script of Mesopotamia and adopted the alphabet. This proved immensely attractive and spread far and wide. Thus it was received in Yemen, even though this remote region had shown no interest in earlier writing systems. But what concerns us here is the use of the alphabet to write Aramaic, the language that in the course of the first millennium B.C. displaced the older Semitic tongues of Syria and Mesopotamia in daily life.
Alphabetic writing in Mesopotamia was normally done on perishable materials, not on clay, with the result that little of it has survived. But it seems that even in Mesopotamia the old cuneiform tradition was losing ground to the new alphabetic culture. And it was Aramaic, not Akkadian, that was to be used as the primary written language of administration in the Persian Empire.