Prior to this, the island nation was prosperous and peaceful. Aeretzvy had several major trading ports, and traders from near and far provided many staples as well as more exotic goods. Many writers attest to Aeretzvy's great wealth in gems and precious metals, the industriousness of its people, and the sophistication of its philosophers.
At some point, around 300 B.E.D., the influx of traders and travelers ended, more or less abruptly.
In the initial period of confusion and worry, the Aeretzvians sent out scouting ships to nearby islands they had previously enjoyed regular trade with. These sailors were uniformly unable to locate a single island.
Popular theories at the time postulated that great demons from far beneath the ocean's surface had dragged down ships and entire islands, and that they would in time come for Aeretzvy; or that Aeretzvy itself had come unmoored and floated away; or that some strange substance in the air surrounding the island had addled local and foreign sailors alike, leading them hopelessly off course.
As resources dwindled and apocalyptic sentiment grew, with no sign of humanity or even solid land outside of Aeretzvy's shores, attention shifted from theorizing to hoarding, infighting, and looting.
Some Aeretzvians, pessimistic about the prospects of their nation, set sail in all directions. Some of those landed at the Saint Montaigne Delta region, and built the civilization that would give rise to the Experimental Duchies. The ultimate results of the events on Aeretzvy, naturally, remain unknown.
Recently, divers have discovered a remarkably well-reserved wrecked ship which researchers speculate may be Aeretzvian in origin, from about this time period. Exploration of the wreck is scheduled to begin soon.