Kutadgu Bilig is one of the most important works in Turkish literature in the 11th century. It is one of the oldest works belonging to the Turkish literature in the Islamic period. It was written by Yusuf Khass Hajib in the period of the Karakhanids. At the time of the Karakhanids, the Turks had accepted Islam as the official religion of the state. The writing of Kutadgu Bilig takes places almost a century after the Turks had accepted Islam. Kutadgu Bilig was written in the year 1069. Yusus Khass Hajib completed this work in eighteen months. Yusuf Khass Hajib presented this work to Ebu Ali Hasan bin Suleyman Arslan, whose title was `Eastern Karakhanid Sultan Tabgach Ulugh Bughra Kara Khan'.