How could slaves become free under Abbasid rule?

Under Abbasid rule, slaves could gain their freedom through several means. They could be emancipated by their owners, often as an act of charity or in fulfillment of a promise made in a will. Additionally, slaves had the option to buy their own freedom, known as "mukataba," by negotiating a payment plan with their masters. Some slaves also gained freedom through military service, where their valor in battle could lead to manumission.