HASAN UL-BASRI (Abu Saud ul-Hasan ibn Abi-l-Hasan Yassar ul-Basri) (642-728 or 737), Arabian theologian, was born at Medina, the son of a freedman of Zaid ibn Thabit, one of the Ansar (Helpers of the Prophet). He became a teacher of Basra and founded a school there, where among his pupils was Wasil ibn `Ata, the founder of the Mo`tazilites. He himself was a great supporter of orthodoxy and practised ascetism. With him fear is the basis of morality, and sadness the characteristic of his re ligion. In politics he adhered to the earliest principles of Islam, being strictly opposed to the inherited caliphate of the Omayyads and a believer in the election of the caliph.