The island of Kos was famous and in great demand throughout antiquity for its school of medicine founded by Hippocrates. Alexander the Great liberated the island from Persian rule in 333 BC. After his death, however, Kos became the apple of discord once again.
Who ever issued coins on Kos tried to legitimate his claim for power by minting in the succession of Alexander the Great. Alexander's coins were therefore resumed basically unchanged, except for the images on the reverse that were adapted to the respective political circumstances. This tetradrachm depicts Alexander in the guise of the Greek hero Heracles wearing a lion's scalp. The reverse shows a crab.