They were basically slaves but not legally slaves. They couldn't leave the plantation(long termI mean, they could physically leave to go do things) and they didn't get paid in real money and they could be punished corporeally. They could be shot for going onto land of someone who wanted to shoot them, including during medical emergencies where they would have spend extra hours or days going around massive estates to carry someone to the hospital. Conditions varied but like, that was the general deal.