Going back to around 2500BC, it is thought to have been Hatti The Land of the Hattites, not to be confused with the later Hittites.
Prior to 1923 - whilst the land was populated by Turks, it was referred to as the Ottoman State, made up of small principalities such as the Anatolian Beyliks or Turkmen Beyliks.
S�leyman the Magnificent united the present territories of Turkey in the 1530s. But generally speaking, it has nearly always been since 3000BC or so, Anatolia. As contained in the poem by Suleimen himself to his favourite harem girl:
�..My springtime, my merry faced love, my daytime, my sweetheart, laughing leaf�
My plants, my sweet, my rose, the one only who does not distress me in this world�
My Istanbul, my Caraman, the earth of my Anatolia
My Badakhshan, my Baghdad and Khorasan
My woman of the beautiful hair, my love of the slanted brow, my love of eyes full of mischief�