The history of the world is the recorded memory of the experience, around the world, of Homo sapiens. Ancient human history begins with the invention, independently at several sites on Earth, of writing, which created the infrastructure for lasting, accurately transmitted memories and thus for the diffusion and growth of knowledge.Webster, H. (1921). World history. Boston: D.C. Heath. Page 27.

Human history is marked both by a gradual accretion of discoveries and inventions, as well as by quantum leaps — paradigm shifts, revolutions — that comprise epochs in the material and spiritual evolution of humankind.

One such epoch was the advent of the Agricultural Revolution. Between 8,500 and 7,000 BCE, in the Fertile Crescent, humans began the systematic husbandry of plants and animals — agriculture. This spread to neighboring regions, and also developed independently elsewhere, until most Homo sapiens lived sedentary lives in permanent settlements as farmers.

Not all societies abandoned nomadism, especially those in isolated regions that were poor in domesticable plant species. Those societies, however, that did abandon nomadism adopted settled life in scattered habitations centered about life-sustaining bodies of water — rivers and lakes. These communities coalesced over time into increasingly larger units, in parallel with the evolution of ever more efficient means of transport.

The relative security and increased productivity provided by farming allowed these communities to expand. Surplus food made possible an increasing division of labor, the rise of a leisured upper class, and the development of cities and thus of civilization. The growing complexity of human societies necessitated systems of accounting; and from this evolved, beginning in the Bronze Age, writing. The independent invention of writing at several sites on Earth allows a number of regions to claim to be cradles of civilization.

Civilizations developed perforce on the banks of rivers. One of the first civilizations to arise, between 4,000 and 3,000 BCE, was Sumer, in the Middle East's "land between the rivers"—Mesopotamia. Other civilizations soon developed on the banks of the Nile River in ancient Egypt, at the Indus River valley, and along the great rivers of China.

The history of the Old World is commonly divided into:

• Antiquity — in the Ancient Near East, the Mediterranean basin of Classical Antiquity, Ancient China, and Ancient India, up to about the 6th century;
• the Middle Ages, from the 6th through the 15th centuries;
• the Early Modern period, including the European Renaissance, from the 16th century to about 1750; and
• the Modern period, from the Age of Enlightenment and the Industrial Revolution, beginning about 1750, to the present.