Linguist. Kaşgarlı Mahmut, is known to have come from the lineage of Karahanlılar and to have been living around the same period as Yusuf Has Hacip, who wrote Kutadgu Bilig. Kaşkarlı Mahmut presented his famous work Divan-u Lügatit Türk (Dictionary of the Turkish Language), which he began to write on 25 january 1072 in Baghdad and finished writing on 10 february 1074. This dictionary was written in Arabic in order to teach the Arabians Turkish and to prove that Turkish language is rich, gave very valuable information about the language and folklore of the Turkish tribes who lived in 11. century in his work Divan-u Lügatit Türk.This book known as the first Turkish Grammar book, it was found by chance in Istanbul after 1908. According to this book, his family emigrated from Kaşgar to Iraq. At that time Iraq was one of the best islamic culturel place. Because of this, it is the most imported for people who worked about islamic science. In 1080, he backed to Kaşgar.