About 1000 BC new powers arose in several parts of the world, overwhelmed the existing order, and took its place. Warfare was conducted on an entirely new scale. Egypt was challenged by its former subject peoples from Sudan; in Iraq a new military power, the Assyrians, built an empire that eventually covered much of the Middle East; and in China, a group of outsiders, the Zhou, overthrew the long-established Shang Dynasty. There were also profound changes in economic behaviour: in both what is now Turkey and China coins were used for the first time, leading to a rapid growth of commercial activity. Meanwhile, quite separately, the first cities and complex societies in South America began to emerge.