The increase in food production brought by the development of plow agriculture allowed Neolithic villages to grow ever larger. By 7000 B.C.E. or so, some villages in the Fertile Crescent may have had as many as ten thousand residents. One of the best known of these, Çatal Hüyük in what is now modern Turkey, shows evidence of trade as well as of the specialization of labor. Çatal Hüyük’s residents lived in mud-brick houses whose walls were covered in white plaster. The men and women of the town grew wheat, barley, peas, and almonds and raised sheep and perhaps cattle, though they also seem to have hunted. They made textiles, pots, figurines, baskets, carpets, copper and lead beads, and other goods. They gathered, sharpened, and polished obsidian, a volcanic rock that could be used for knives, blades, and mirrors, and then traded it with neighboring towns. From here the obsidian was exchanged still farther away, for Neolithic societies slowly developed local and then regional networks of exchange and communication.

Among the goods traded in some parts of the world was copper. Pure copper occurs close to the surface in some areas, and people, including those at Çatal Hüyük, hammered it into shapes for jewelry and tools. More often, copper, like most metals, occurs mixed with other materials in a type of rock called ore, and by about 5500 B.C.E. people in the Balkans had learned that copper could be extracted from ore by heating it in a smelting process. (See “Individuals in Society: The Iceman.”) Smelting techniques were discovered independently in many places around the world, including China, Southeast Asia, West Africa, and the Andes region. Pure copper is soft, but through experimentation artisans learned that it would become harder if they mixed it with other metals such as arsenic, zinc, or tin during heating, creating an alloy called bronze.

Because it was stronger than copper, bronze had a far wider range of uses, so much so that later historians decided that its adoption marked a new period in human history, the Bronze Age. It began about 3000 B.C.E. in some places, and by about 2500 B.C.E. bronze technology was having an impact in many parts of the world, especially in weaponry. The end of the Bronze Age came with the adoption of iron technology, which also varied in its beginnings from 1200 B.C.E. to 300 B.C.E.

Objects were not the only things traded over increasingly long distances during the Neolithic period, for people also carried ideas as they traveled. Knowledge about the seasons and the weather was vitally important for those who depended on crop raising, and agricultural peoples in many parts of the world began to calculate recurring patterns in the world around them, slowly developing calendars. Scholars have demonstrated that people built circular structures of mounded earth or huge upright stones to help them predict the movements of the sun and stars.

The rhythms of the agricultural cycle and patterns of exchange also shaped religious beliefs and practices. Shamans and priests developed ever more elaborate rituals designed to assure fertility, in which the gods were often given something from a community’s goods in exchange for their favor. In many places gods came to be associated with patterns of birth, growth, death, and regeneration. Like humans, the gods came to have a division of labor and a social hierarchy. Thus, as human society was becoming more complex, so was the unseen world.