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
Astypalaia Astypalaia Astypalaia (Greek: Αστυπάλαια, ), is a Greek island with 1,334 residents (2011 census). It belongs to the Dodecanese, an archipelago of twelve major islands in the southeastern Aegean Sea. The island is long, wide at the most, and covers an area of 97 km. Along with numerous smaller uninhabited offshore islets (the largest of which are Sýrna and Ofidoussa), it forms the Municipality of Astypalaia, which is part of the Kalymnos regional unit. The municipality has an area of 114.077 km. The capital and the previous main harbour of the island is Astypalaia or Chora, as it is called