By 7000 B.C.E. or so, some agricultural 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 Turkey, shows evidence of trade as well as specialization of labor. Çatal Hüyük’s residents lived in densely packed mud-brick houses with walls covered in white plaster that had been made with burned lime. 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, and decorated their houses with murals showing animal and human figures. 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, obtaining seashells and flint. 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, which people hammered into shapes for jewelry and tools. Like most metals, in its natural state copper usually 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. Smelted copper was poured into molds and made into spear points, axes, chisels, beads, and other objects. (See “Living in the Past: The Iceman.”) Pure copper is soft, but through experimentation artisans learned that it would become harder if they mixed it with other metals such as zinc, tin, or arsenic 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. Like all new technologies, bronze arrived at different times in different places, so the dates of the Bronze Age vary. 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. The end of the Bronze Age came with the adoption of iron technology, which also varied from 1200 B.C.E. to 300 B.C.E. All metals were expensive and hard to obtain, however, so stone, wood, and bone remained important materials for tools and weapons long into the Bronze Age.

Objects were not the only things traded over increasingly long distances during the Neolithic period, for people also carried ideas as they traveled on foot, boats, or camels, and in wagons or carts. 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, including Nabta Playa, erected about 4500 B.C.E. in the desert west of the Nile Valley in Egypt, and Stonehenge, erected about 2500 B.C.E. in southern England.

The rhythms of the agricultural cycle and patterns of exchange also shaped religious beliefs and practices. Among foragers, human fertility is a mixed blessing, as too many children can overtax food supplies, but among crop raisers and pastoralists, fertility — of the land, animals, and people — is essential. Thus in many places multiple gods came to be associated with patterns of birth, growth, death, and regeneration in a system known as polytheism. Like humans, the gods came to have a division of labor and a social hierarchy. There were rain-gods and sun-gods, sky goddesses and moon goddesses, gods that ensured the health of cattle or the growth of corn, goddesses of the hearth and home.