Once people began settling down into more sedentary groups, some of the first urban centers and cities emerged. With more food being produced, they no longer had to search for food, and could focus on other things like development of technology, art, science, etc. Different social structures also arose as a hunter-gatherer structured society was no longer needed. Social classes depending on occupation or wealth developed. Different governmental structures emerged. Trade with other groups began and they shared knowledge and technology. A newfound need to protect themselves and everything they've achieved also helped spawn new ideas of warfare.
