The last glacial age, which ended roughly 12,000 years ago, brought warmer, wetter conditions to the Near East. The "Fertile Crescent" — covering parts of today's Turkey, Syria, Israel, Jordan, Iraq and Iran — already hosted dense stands of wild wheat (einkorn, emmer), barley, lentils, and peas that grew naturally with the spring rains. Late hunter-gatherer groups such as the Natufians were already harvesting these plants intensively, cutting them with flint sickles and grinding them on stone mortars: the infrastructure of agriculture was being built before agriculture itself.

Between about 10,000 and 8,500 BCE a threshold was crossed: people began not merely to gather but to sow, harvest, store, and set aside seed for next season. Plants with larger grains and tougher rachises (so the grain stays on the stalk for harvest) were unknowingly selected; within a few centuries these traits became genetically fixed. In parallel, goats, sheep and cattle were domesticated.

Agriculture did not begin in one place. Rice and millet in China (from around 8,000 BCE), taro in New Guinea, maize in Mesoamerica and the potato in the Andes were domesticated independently. The consequences were global: settled life, larger populations, the idea of property, the spread of disease, social stratification, taxation, the state — the layered structure we call civilisation rests on this threshold. At the same time, narrower diets and rising infectious disease meant early farmers were often less healthy than their hunter-gatherer ancestors, a paradox historians still debate.