Before [the Kencyrath] arrived on Rathillien, the natives say that in [the Southern Wastes'] place was a huge inland sea surrounded by rich civilizations. Then the climate changed from temperate to a desert, don't ask me why or how. They say that even the stars shifted in the sky. Anyway, the sea was cut off from its freshwater sources, turned to salt, and dried up. The cities that clustered around it disappeared into the sand and their people fled. Only their outposts remained—Kothifir, Hurlen, and Urakarn, for example. All of this was some three thousand years ago, during the Fifth Age.
– Index, Honor's Paradox, "Chapter VI: History Lessons", I