At the beginning of the Pharaoh Akhenaton period, the supreme power in Mesopotamia was Mitanni. As the ally of Egypt it constituted a buffer state on the borders of North Syria, which prevented the southern expansion from Asia Minor of the Hittite confederacy and the western expansion of aggressive Assyria, while it also held in check the ambitions of Babylonia, which still claimed the "land of the Amorites". So long as Mitanni was maintained as a powerful kingdom the Syrian possessions of Egypt were easily held in control, and the Egyptian merchants enjoyed preferential treatment compared with those of Babylonia. But when Mitanni was overcome, and its territories were divided between the Assyrians and the Hittites, the North Syrian Empire of Egypt went to pieces. A great struggle then ensued between the nations of western Asia for political supremacy in the "land of the Amorites". Babylonia had been seriously handicapped by losing control of its western caravan road. Prior to the Kassite period its influence was supreme in Mesopotamia and middle Syria; from the days of Sargon of Akkad and of Naram-Sin until the close of the Hammurabi Age its merchants had naught to fear from bandits or petty kings between the banks of the Euphrates and the Mediterranean coast. The city of Babylon had grown rich and powerful as the commercial metropolis of Western Asia. Separated from the Delta frontier by the broad and perilous wastes of the Arabian desert, Babylonia traded with Egypt by an indirect route. Its caravan road ran northward along the west bank of the Euphrates towards Haran, and then southward through Palestine. This was a long detour, but it was the only possible way. During the early Kassite Age the caravans from Babylon had to pass through the area controlled by Mitanni, which was therefore able to impose heavy duties and fill its coffers with Babylonian gold. Nor did the situation improve when the influence of Mitanni suffered decline in southern Mesopotamia. Indeed the difficulties under which traders operated were then still further increased, for the caravan roads were infested by plundering bands of "Suti", to whom references are made in the Tell-el-Amarna letters. These bandits defied all the great powers, and became so powerful that even the messengers sent from one king to another were liable to be robbed and murdered without discrimination. When war broke out between powerful States they harried live stock and sacked towns in those areas which were left unprotected. The "Suti" were Arabians of Aramaean stock. What is known as the "Third Semitic Migration" was in progress during this period. The nomads gave trouble to Babylonia and Assyria, and, penetrating Mesopotamia and Syria, sapped the power of Mitanni, until it was unable to resist the onslaughts of the Assyrians and the Hittites.