Dhimmis were allowed to operate their own courts following their own legal systems in cases that did not involve other religious groups, or capital offences or threats to public order.[6] Non-Muslims were allowed to engage in religious practices that was usually forbidden by Islamic law, such as the consumption of alcohol and pork, as well as religious practices which Muslims found repugnant, such as the Zoroastrian practice of incestuous "self-marriage" where a man could marry his mother, sister or daughter. According to the famous Islamic legal scholar Ibn Qayyim (1292-1350), non-Muslims had the right to engage in such religious practices even if it offended Muslims, under the conditions that such cases not be presented to Islamic Sharia courts and that these religious minorities believed that the practice in question is permissible according to their religion.[7]