So many people lived on this fertile island in Mycenaean times that Kos was rich enough to send 30 ships to the Trojan War. In 477 BC, after suffering an earthquake and subjugation to the Persians, it joined the Delian League and again flourished. Hippocrates (460–377 BC), the Greek physician known as the founder of medicine, was born and lived on the island. After his death, the Sanctuary of Asclepius and a medical school were built, which perpetuated his teachings and made Kos famous throughout the Greek world.
That Ptolemy II of Egypt was also born on Kos secured the island the protection of Egypt. It became a prosperous trading centre, but fell under Roman domination in 130 BC and was administered by Rhodes from the 1st century AD onwards. Kos has shared the same ups and downs of fortune ever since, including conquest and/or occupation by the Knights, the Ottomans and the Italians and, much like Rhodes, its economy is now heavily dependent on tourism.