What are the reasons for the transition of tribes from a system of self-government to a system of sole authority?

As material inequality developed, so did inequality in governance. The wealthier members of the community began to exert an increasing influence on government. In the assembly of the people, the word of such people becomes decisive. The power of the leader was now preserved in times of peace and gradually began to pass by inheritance. With increasing inequality, many customs and traditions ceased to effectively regulate life. The leaders had to resolve disputes between their fellow tribesmen, punish them for misdeeds that could not have happened before. For example, after individual families acquired property, theft arose, which was not known before, since everything was common.
Increased clashes between tribes contributed to the development of inequality. During the Paleolithic period, tribal wars were quite rare, but since the beginning of the Neolithic revolution they have been fought almost constantly. Individual communities and tribes in a productive economy could accumulate significant food reserves, which other tribes sought to appropriate.
For successful defense and attacks, the tribes united in tribal alliances led by a warlord. The best warriors rallied around the leaders.

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