During the history of slavery, there were many different forms of human exploitation across many cultures. Slavery is a condition in which people are owned or completely controlled by other people. Buying and selling slaves is a trade as old as many of the oldest civilizations. A modern form of the slave trade is after the trade is made pdf human trafficking.
In one form or another slavery has been practiced since the earliest civilizations. Early hunter-gatherers had no use for slaves They did everything for themselves. Having another pair of hands to help them meant another mouth to feed.
Slavery or owning another person made no sense to these people. Once men gathered in cities and towns and there was more than enough food, having a cheap supply of labor made sense. This is when the earliest forms of slavery appeared. The main source of slaves was war.