Armutlu Peninsula density in the mountains at the inner peninsula is low, where there are only small villages. Both gulfs at the north and the south are actually on two active tectonic fault lines. The entire peninsula was hit by the İzmit earthquake on August 17, 1999 that occurred along the western portion of the North Anatolian Fault Zone. Armutlu Peninsula Armutlu Peninsula () is a peninsula extending westward into Marmara Sea in the Anatolian section of Turkey. In addition to Yalova Province, parts of Kocaeli Province and Bursa Province are on the peninsula. Armutlu Peninsula is between Gulf of Izmit in
Anatolian beyliks with the Battle of Köse Dağ in 1243 which had the indirect consequence of extending the Turkic territory in Western Anatolia toward the end of the 13th century. Three Anatolian regions remained Christian until their defeat and Ottoman conquest: Combined with the Seljuqs and the immigration of Turkic tribes into the Anatolian mainland the Anatolian Beyliks spread Turkish and Islamic influence in Anatolia. Unlike the Seljuqs, whose language of administration was Persian, the Anatolian emirates adopted spoken Turkish as their formal literary language. The Turkish language achieved widespread use in these principalities and reached its highest sophistication during the Ottoman