According to Chinese sources Turkish literature began in the 
2nd century BC but the extant records are those of Orhon cuneiforms,
generally dated 8th century AD. As the Turks moved westward different
branches of the language came into existance. The most important is
Cagatay, which evolved its own literature quite separate from Ottoman.
There is also Oguz, the forerunner of modern Turkish: the most notable
work it produced is ``The  Book of Dede Korkut,'' whose prose narrative
is punctuated with superb verses. Ottoman literature began about the 
early 13th century, soon founding in poets like Yunus Emre and Esrefoglu
a mystical tradition of considerable value in Islamic culture. Persian
forms began to exercise an influence on Ottoman poets, who gradually
adopted and used them, creating a new Turkish language now known as
Osmanli. Persian-inspired poetry began in the mid 16th century, reaching
its peak perhaps in work of Nedim, the most prominent and the most
Turkish poet of Lale Devri (The Age of Tulips). Westernisation started
in the late 19th century, and the work of Ahmed Hasim and his contemporaries
combines Persian metres with themes prompted by the French Symbolists.
The emergence of modern Turkey produced a poetry more aware of its local,
popular roots: poets turned to the syllabic metres of folk poetry, and
the old Osmanli literary style gave way to the more direct language
characteristic of most Western poetry today. The incomparable Nazim Hikmet
and is generation demonstrate the great advance Turkish poetry has made
this century; the bulk of what follows bears a witness to a vigorous modern
presence embracing both Eastern and Western concerns.

from Poetry of Asia
     Five Milleniums of Verse from Thirty-three Languages
     Weatherhill - 1979

     general ed. Keith Bosley
     Turkish section edited by Taner Baybars