The three principal ways civilization spreads from one region to another is through trade, travel and warfare. When people travel, they bring with them goods from their region to another and this would be the start of contributing and sharing, and trading their ways and ideas of growing crops and raising other goods. It can also be spread through wars. Through this, different relationships emerged.
Observe current cultures, such as the city you live in, if you live in a city, or Toronto, New York, any city really. It is approximately the same to early cultures. Thus, the creation of cities required a much more complex, authoritative, and larger government to sustain them. Cities are a problem and should not exist -- the government is basically a system to help prolong the inevitable death of a city. I am not meaning to be negative, or pessimistic, but it is quiet true.
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