During the reign of the early Abbasides the Shi'a Imam Ja'far al-Sadiq preached against slavery, and his views were adopted by the Mu'tazila. Karmath, who flourished in the ninth century of the Christian era..seems to have held slavery to be unlawful.
Lakini hata kabla ya tume kuanza kazi yake ya uchunguzi, msema-ji wa Vatican alikubali kuwepo kwa "ukweli" kwenye taari-fa hiyo, ingawaje katika kutimiza wajibu wa kazi yake alilaumu gazeti la Sunday Times kwa uchuuzaji wake wa hisia za watu.