Historical evidence about Chalki is scarce. The island passed through the centuries in the shadow of Rhodes, and its history can only be outlined in its key points in relation to the history of Rhodes and the broader region of the southeastern Aegean.
Chalki, which can be considered one of the “last beacons of tradition,” likely took its name from the copper processing mines that existed on the island in antiquity. Chalki has been inhabited since prehistoric times. According to mythology, the Titans were the first inhabitants of the island. The Pelasgians lived on the island for many years, leaving behind numerous structures. They were succeeded by the Carians, the Dorians, and later the Phoenicians. The Queen of Chalki, Aretanassa, lived on the island until she was exiled to Karpathos, where she committed suicide upon hearing of her husband’s death. Remnants of three temples dedicated to the god Apollo still exist at the site of Pefkia. In historical times, Chalki was occasionally mentioned as a subject of Kamiros and was referred to as an “ally” of the Athenians in the annual “tax lists of the Delian League,” which indicates that it had come under the administrative dependence of the “Athenian Democracy” during that period. Later, it seems to have come under the control of Kamiros once more. The island then followed the rise and fall of Rhodes in the ensuing centuries.
In the 7th century, the island was seized by the Arabs until 825, when it was liberated. The Venetians and Genoese arrived in 1204 and repaired the ancient acropolis, while simultaneously building a fortress on the islet of Alimia. In the 14th century, the Knights of Rhodes granted Chalki as a fief to the Assanti family from Ischia. During that time, they built their castle on the ruins of the ancient acropolis. Among the coats of arms preserved, there is the coat of arms of the Grand Master Pierre d’ Aubusson (1476–1530), who restored the fortress after a destructive raid by the Venetians. The castle served as a refuge for the population in case of an invasion. In 1523, the Turks seized Chalki.
Chalki took part in the Greek Revolution of 1821. From the mid-19th century, under Ottoman rule, the island reached the peak of its prosperity. Along with Symi, Kalymnos, Kastelorizo, and Kasos, Chalki developed commerce and sponge fishing. Schools were established, and the educational level of the population saw a sharp rise.
In the later years of Ottoman rule and during the Italian occupation, traditional privileges were abolished, affecting trade and sponge fishing, leading to a wave of emigration. The island was seized by the Italians in 1912, along with the rest of the Dodecanese, coming under Italian control, initially military and later political after 1923.
During World War II, Chalki gained honor due to the struggles and the sacrifices of its brave people, such as Lieutenant Alexandros Diakos and Captain Diogenes Fanourakis.