Early communities made up of extended families settled south of the Sahara Desert by rivers. These waterways enabled trade with other communities, allowing them to obtain goods which they could not produce. The water also fertilized the soil and provided people with fish. Family communities often included 15 to 20 members.
Family communities often ended up joining forces in times of danger. Sometimes, they even built whole walls to protect themselves from invaders. Over time, families joined together creating villages. Together, they were able to accomplish greater things than they could have alone. Villages often contained one-hundred to two-hundred people.
Before long, villages developed into towns and cities. The ability to make iron tools made farming quicker and easier, creating a surplus of crops. Places that produced a surplus of crops often became busy trading sites as the residents had time to specialize in crafts and trades, such as weaving, which could be traded. Villages located along rivers soon became wealthy as many people could travel by water to trade there.
Empires developed when a surplus of crops provided the time to create luxury goods and time to focus on military strength as well as the production of weopons. Wealth from tributes and trade covered the expenses of a growing military. Large militaries conquered important trading sites and gained control over the gold trade. Kingdoms could tax traders on their goods, giving them the money to protect trade routes.