In the early centuries of Islam, a group of religious-minded people called sufis turned to asceticism and mysticism in protest against the growing materialism of the Caliphate as a religious and political institution. They were critical of the dogmatic definitions and scholastic methods of interpreting the Qur’an and sunna (traditions of the Prophet) adopted by theologians. Instead, they laid emphasis on seeking salvation through intense devotion and love for God by following His commands, and by following the example of the Prophet Muhammad whom they regarded as a perfect human being. The sufis thus sought an interpretation of the Qur’an on the basis of their personal experience. By the eleventh century, Sufism evolved into a well-developed movement with a body of literature on Quranic studies and sufi practices. Institutionally, the sufis began to organise communities around the hospice or khanqah (Persian) controlled by a teaching master known as shaikh (in Arabic), pir or murshid (in Persian). He enrolled disciples (murids) and appointed a successor (khalifa). He established rules for spiritual conduct and interaction between inmates as well as between laypersons and the master.