The prevailing theory is that the Insula Sea was untouched until it was discovered hundreds of years ago by the first explorers from over the Endless Ocean.
It’s the belief of some, however, that the Insula Sea is much, much older. That it had thriving civilizations before some great cataclysmic event occurred, maybe over a thousand years ago. There are ancient structures scattered over the mainland and islands that are too old to be explained. Mainstream academia has dismissed them.
Some archeologists, such as Professor Andrews, look to find evidence supporting of this event.