In the ninth century BC a powerful kingdom arose in northern Sudan (Kush). Conquering Egypt, its kings ruled the Nile Valley, from the Mediterranean to as far as Khartoum, for half a century. This was a dramatic historical period, dominated by the expansion of the Assyrian empire into Syria and Palestine. The Nubians supported the kings of Israel against Assyria, but eventually Egypt itself was invaded. Allied with the Assyrians, the Libyan Princes of Sais succeeded in ousting the Nubians and re-uniting Egypt under their own rule. Despite these constant wars, this was also a period of artistic renaissance, attested by many building works in Egypt and Sudan, by a striking series of portrait sculptures, and the splendid burial treasures of the royal family. Withdrawal from Egypt did not mark the end of the Kushite state, which continued for nearly a thousand years.