Around 5800 BCE arose the first known farming communities: in the rich alluvial soil of Mesopotamia. Villages dotted the banks of the Euphrates river.
(Other parts of the world, notably China, were likely to have had contemporaneous agricultural communities. The attribution of Mesopotamia as first owes to archeological discovery and its lack thereof at disparate locales.)
By 5500 BCE farmers had started diverting floodwaters from the Euphrates and Tigris rivers onto their fields, then draining them to prevent salt buildup in the soil. Some irrigation canals extended 5 kilometers from the river.
The largest cluster of villages covered 11 hectares: home to 2,500–4,000 people. Villages were linked by kin ties which facilitated leadership and cooperative coordination: essential skills needed to survive a harsh environment.