The history of Kalymnos is parallel to the history of the other Dodecanese islands. Kalymnos has been inhabited since the pre-Minoan times. During the Archaic period, the distance of the Dodecanese from Athens gave autonomy to these islands, including Kalymnos, and freedom from the imperial Athens. With the rise of the Macedonian Empire, Kalymnos, as well as the other islands of the group, became part of it.
After the death of Alexander the Great, one of its successors, Ptolemy I of Egypt, took control of all the islands of the Dodecanese. The inhabitants of the group were the first Greeks to convert to Christianity because Saint Paul and Saint John made a stop there to preach their faith. During the Early Byzantine Times, Kalymnos was flourishing, like all the other islands of the group, but by the 7th century AD, the invaders took advantage of the vulnerable strategic position of those islands.
In the 14th century, the Knights of Saint John ruled Kalymnos, along with all Dodecanese islands, and built the Castle of Cryssocheria to protect it. The Turkish rule followed in 1522 and ended in 1912 when the Italians took their place. When the Italians surrendered, the Germans and the British fought to take control over the islands of the Dodecanese, causing great damages and sufferings among the population. Kalymnos was united to the newly built Greek State with the rest of the Dodecanese in 1947. In the 1960s, the economy of Kalymnos, based on sponge fishing, gradually declined and many residents migrated.