Sufism or mysticism emerged in the 8th century. Some of the early known Sufis are as follows: Rabia al-Adawiya, Al-Junaid, and Bayazid Bastami. Sufism evolved into a well-developed movement by the end of the 11th century.
Barani was a contemporary of Muhammad bin Tughlaq and Firuz Shah Tughlaq both. He wrote a number of renowned texts, such as the Fatwa-i-Jahandari, which elaborates on the principles to be followed by Muslim rulers to attain merit.