Disaster / Destruction
The Smothering is the name of a long period of decreased sunlight, heralded by worldwide disasters including major earthquakes, volcanic eruptions, tsunamis, and ash falling from the sky. In addition to the enormous devastation caused by these disasters, the decreased sunlight caused worldwide crop failures, causing many civilizations to collapse. The effects of the Smothering were the most severe in Thescel, the heart of the Lehmer Empire. Some Thescan refugees reported fire raining from the sky, and all contact was lost with a good part of the continent.
The cause of the Smothering is uncertain, but everybody has a theory - evil cults, a supervolcano, a magical accident, an asteroid, dragons, fiends, the gods, or even birds somehow getting their revenge on the surface world. Over time, sunlight gradually returned to the world, and the Smothering is generally considered to have ended between 225 and 230, by which point the world was beginning to recover and rebuild.