Antiquity
Thucydides stressed the special importance of the bays and the harbours of Leros during the Peloponnesian War (431 BC – 404 BC), where Leros supported the democratic Athenians. After the end of the war Leros came under the sovereignty of the Spartans. The island had a famous sanctuary of the goddess Artemis.
It then followed the fate of the rest of the Dodecanese Islands during the years of Alexander the Great and his successors, the Roman years and the Byzantine period. After the division of the Roman Empire, Leros was part of the Byzantine Empire. On the island of Farmaco east from Leros, a few miles from Didyma on the Turkish coast, Julius Caesar was held as a hostage by local pirates for forty days.
Venetian and Ottoman Era
During the Byzantine Age, the island was incorporated into the Theme of Samos. During the thirteenth century, the island was occupied by the Genoese and then by the Venetians. In the year 1309, the Knights of St John seized and fortified Leros. In 1505, the Ottoman Admiral Kemal Reis, with three galleys and seventeen other warships, besieged the castle but could not capture it. The operation was repeated in 1508 with more ships, but again nothing was achieved.
Legend has it that then the island was rescued by the only surviving knight, barely 18 years old. He dressed women and children in the armor of the dead defenders, convincing the Ottomans that the garrison of Leros was still strong. Finally, on 24 December 1522, following the siege of Rhodes, a treaty was signed between Sultan Suleiman and the Grand Master of the Knights, Philippe Villiers de L'Isle-Adam, and Leros, along with all the Aegean possessions of the Order, passed into Ottoman hands which ruled the island with brief interruptions during a period of four hundred years.
During the Ottoman rule, and along with the other islands, Leros enjoyed a privileged regime, with partial autonomy and self–government
