The Caliph Umar ibn Abdulaziz found it hard to accept how non-Muslims continued to follow their social regulations that went against the Islamic injunctions.  He wrote a letter to Hasan al-Basri seeking his legal advice, saying, ‘How is it that the Rightly-Guided Caliphs before us left the People of the Covenant as they did, marrying close relatives, and keeping pigs and wine?’  Hasan’s responded, ‘They paid the Jizya so that they could be left to practice what they believed, and you may only follow the Islamic Law, not invent something new. (Maududi, ‘The Rights Of The People of Covenant In The Islamic State. p. 22)