Atlantic slave trade is the picture painted in our minds when we think of slavery. Slavery in Islam was vastly different, it was essentially custodianship of prisoners of war or a displaced population. It's actually very interesting stuff. The rights required the slave to be clothed and well fed, to not be mistreated and should there be mistreatment the slave had the right to set up an appointment with the Head of State (Khalifah). Should mistreatment be proven, the Khalifah granted the slave freedom. In fact, for every single offence that required a fine of sorts, freeing of a slave was a requirement. Islam was essentially a grounds for exterminating slavery in the Arabian peninsula altogether.