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
Dodecanese and Kos had Turkish communities) leaned heavily towards Greece following its declaration of independence in 1822, and many of the islanders joined the Greek War of Independence, with the result that the northern portion of the Dodecanese (including Samos) became briefly the Greek provinces of the Eastern Sporades and Southern Sporades. Kasos in particular played a prominent role due to its skilled mariners, until its destruction by the Egyptians in 1824. Most of the islands were slated to become part of the new Greek state in the London Protocol of 1828, but when Greek independence was recognized in the London