Dodecanese Symi, Tilos, and Kastellorizo. Other islands in the chain include Alimia, Arkoi, Chalki, Farmakonisi, Gyali, Kinaros, Levitha, Marathos, Nimos, Pserimos, Saria, Strongyli, Syrna and Telendos. The name "Dodecanese" (older form ἡ Δωδεκάνησος, "hē Dōdekanēsos"; modern τα Δωδεκάνησα, "ta Dōdekanēsa"), meaning "The Twelve Islands", denotes today an island group in the southeastern Aegean Sea, comprising fifteen major islands (Agathonisi, Astypalaia, Chalki, Kalymnos, Karpathos, Kasos, Kastellorizo, Kos, Lipsi, Leros, Nisyros, Patmos, Rhodes, Symi, and Tilos) and 93 smaller islets. Since Antiquity, these islands formed part of the group known as the "Southern Sporades" (Νότιες Σποράδες). The name "Dōdekanēsos" first appears in Byzantine
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