Asia
The coastal periphery was home to some of the world's earliest known civilizations, each of them developing around fertile river valleys. The civilizations in Mesopotamia, the Indus Valley and the Yellow River shared many similarities. These civilizations may well have exchanged technologies and ideas such as mathematics and the wheel. Other innovations, such as writing, seem to have been developed individually in each area. Cities, states and empires developed in these lowlands.
Prehistory
The Bronze Age is the earliest period in which some civilizations have reached the end of prehistory, by introducing written records. The Bronze Age or parts thereof are thus considered to be part of prehistory only for the regions and civilizations who adopted or developed a system of keeping written records during later periods. The invention of writing coincides in some areas with the early beginnings of the Bronze Age. Soon after the appearance of writing, people started creating texts including written accounts of events and records of administrative matters.