In the context of slavery, did female slaves automatically hold the same status as wives? If that is the case, what is the significance of marriage to slaves mentioned in the Qur'an? Why is marriage necessary if ownership implied a marital relationship?
Slavery rules were never started by Muslims but were already existing in different societies of the time when Islam came. Slavery rules are an outcome of wars. Islamic rules aimed to diminish slavery and finish it off. Slavery rules can not be taken as permanent rules for life but only in war and after war under many conditions.
Slave female from war between Nin Muslims against Muslims is not like a full wife of the owner who has the full rights of justice between her and other wife and inheritance from her husband. When the Muslims marries his owned female (Aman), she will then have all rights if the wife. With out marriage, she is called Sariyyah.
Wassalam.