When the Turks started to convert to Islam, beginning in the first half of the tenth century, radical changes occurred in the social life, and these changes were reflected in the literature in terms of language, structure and content. The artists, who went through a transition period between shamanism and the Islamic culture, maintained elements of their previous culture even after they had adopted Islam. They were influenced by the Arabic and Persian languages, which were considered to be the art language of those days, but they did not rush to reflect this influence into their works.
In fact, the Kutadgu Bilig, written in the eleventh century, the first example of Turkish literature which developed under the influence of Islamic culture, was practically written in pure Turkish. Arabic and Persian words are very few in this work, written by Yusuf Has Hacib, which includes views and proposals concerning religion, state, politics and education. One of the most important works of Turkish literature under the influence of Islam is the Divan-i Lugat-it Turk (Dictionary of Turkish Languages) written by Kasgarli Mahmud. This work, which was written to show that Turkish is the language of a rich culture at the same level as the Arabic language, is an encyclopedic dictionary.
Constituting a valuable source of ancient Turkish literature, this work includes a total of 7,500 words from various Turkish dialects and many old Turkish legends and poems. Both the Kutadgu Bilig and theDivan-i Lugat-it Turk are written in Hakaniye Turkish, a southwestern dialect which was referred to as Cagatay Turkish beginning in the fourteenth century when the Cagatay State was established in Western Turkistan, Khorasan and the Khorezm regions. Ali Sir Nevai, who is considered to be one of the greatest masters of Central Asian Turkish literature and who wrote poems, essays on language and dictionaries, and Babur Shah, who wrote his memoirs in the Vekayi Baburname, produced their works in Cagatay Turkish, a dialect which, however, faded out of use in the sixteenth century.
Beginning in the eleventh century, another important development in the Turkish language, which directly influenc-ed the literature later on, occurred in the southwestern dialect, spoken by the Oghuz-Turcoman tribes. Of the Oghuz Turks, those who had settled in Azerbaijan and a part of Iran created the Azerbaijan Turkish, while the dialect of those who had settled in Anatolia eventually developed into the language used in contemporary Turkey.
The influence of Islamic culture on Turkish literature continued from the eleventh century until the mid-nineteenth century. Turkish literature in this period developed in two different and distinct paths, namely, Divan Literature and Folk Literature, two genres which have fundamentally separate characteristics.