Europeans had started trade with Africans which included selling slaves. Once the Europeans had bought the slaves they tightly packed the slaves on a boat with close to no food or water and sent them to South America and the US.
To pay off their debt, as punishment for crimes, and capture by the Europeans and rival tribes. They also became slaves to protect themselves for other people.
In those days there were many ways in which an African could become a slave one of such was when a child need to express his or her feelings the family / community (as Western Education didn't reach them to know the right of a child) will concluded that the child was being stubborn and that child was given to the authority / body that deal with the Europeans who buys the slaves and on the other hand mere greediness could cause it for a father who taught that selling the child out will earn him the money he will use for his God knows what. I'm telling you it was an awful experience because most of these kid made great impact in the country they were sold to.
It originally started when African's were taken unwillingly from there homeland in Africa by white man. When they were captured they were taken aboard a large ship, chained, and stuffed in a cramped narrow room where they stayed for many months until the ship got to America. Through this journey, many died from the living conditions, lack or food/water, ext. The surviving slaves were sold into slavery and auctioned off when they arrived.
It started with slavery. They were brought over packed close together on ships from South Africa to Britan, who later sent them to America
They became slaves to pay for crimes they committed,c
Other nations took them on boats to make them work on their land and on their ships.