Will Durant wrote describing the tolerance of Islam in Medieval Ages where the persecution was the only basis of the relations between religions, cultures and races:

‘At the time of the Umayyad caliphate, the people of the covenant, Christians, Zoroastrians, Jews, and Sabians, all enjoyed degree of tolerance that we do not find even today in Christian countries.  They were free to practice the rituals of their religion and their churches and temples were preserved.  They enjoyed autonomy in that they were subject to the religious laws of the scholars and judges’. (Durant, Will: ‘The Story of Civilization)