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
Syrna (island) Syrna (island) Syrna () or Sirna is a small island about 4 km in area to the south-east of Astypalaia in the Dodecanese group of Greek islands near the south-west coast of Turkey. It is mostly covered with juniper and garrigue scrub. The few inhabitants raise stock, catch fish and practice arable agriculture. The island is important for migrant and breeding seabirds and raptors, including Cory's shearwater, yelkouan shearwater and Eleonora's falcon. A shipwreck of the late Roman period (2nd century CE) was found using sonar technology near the island by the Hellenic Centre for Marine Research in 2000. On