The Cataclysm was a turning point in The Hyborian Age. During the Pre-Cataclysmic Age, Hyboria contained many great civilizations, but the cataclysm rocked the world, rising the Pictish islands in the west to create mountain ranges of a new continent, and sinking the islands of Lemuria and Atlantis. Volcanoes rose on the continent, creating earthquakes that shook down the cities of the great civilizations. Lakes appeared in the middle of the continent.

Some years later, a lesser cataclysm happened, joining the lakes into the Vilayet Sea.