Re: When did the state of Palestine exist before the Jews took over their country?
What you are referring to isn't the "slave trade" it was the migration of south africans to help in irrigation of the fertile crescent.
They were treated unjustly, and within couple DECADES they held a revolt, and the caliph let them go, and governors were punished for their oppressive ways.
Again, please get your history right, especially about Islam.
You do know that Saudi Arabia ended slavery in 1959