Kos Kos Kos or Cos (; ) is a Greek island, part of the Dodecanese island chain in the southeastern Aegean Sea, off the Anatolian coast of Turkey. Kos is the third largest island of the Dodecanese by area, after Rhodes and Karpathos; it has a population of 33,388 (2011 census), making it the second most populous of the Dodecanese, after Rhodes. The island measures , and is from the coast of the ancient region of Caria in Turkey. Administratively, Kos constitutes a municipality within the Kos regional unit, which is part of the South Aegean region. The principal town of
Dodecanese territories, occupied all the present-day Dodecanese except for Kastellorizo. After the end of the war according to the Treaty of Ouchy, Italy maintained the occupation of the islands as guarantee for the execution of the treaty. The occupation continued after Italy declared war on the Ottoman Empire (21 August 1915) during the First World War. During the war, the islands became an important naval base for Britain and France; Italy was allied with both nations during World War I. The Dodecanese were used as a staging area for numerous campaigns, most famously the one at Gallipoli. Some of the smaller