Dodecanese relative quiet and prosperity. In 408 BC, the three cities of Rhodes had united to form one state, which built a new capital on the northern end of the island, also named "Rhodes"; this united Rhodes was to dominate the region for the coming millennia. Other islands in the Dodecanese also developed into significant economic and cultural centers; most notably, Kos served as the site of the school of medicine founded by Hippocrates. However, the Peloponnesian War had so weakened the entire Greek civilization's military strength that it lay open to invasion. In 357 BC, the islands were conquered by
Italian Islands of the Aegean autonomy. Due to the Greek embroilment and defeat in the Greco-Turkish War of 1919–22, these agreements were never implemented. Kastellorizo was temporarily occupied by France in 1915 and came under Italian control in 1921. The Dodecanese islands were formally annexed by Fascist Italy, as the "Possedimenti Italiani dell'Egeo" in 1923. Italian interest in the Dodecanese was rooted in strategic purposes, and the islands were intended to further the Empire's long range imperial policy. The islands of Leros and Patmos were used as bases for the Royal Italian Navy. Starting in 1923, civil governors replaced the military commanders. The Italian politics