Medittus is a tiny Realm at the northern border of Avalon. Where it borders Avalon, there are massive mountains with no visible passes, leading down a tiny peninsula. Medittus itself is an island just north of the peninsula, surrounded by small boat docks and sails.
Medittus was originally founded some five centuries ago, as a sea fortress against northern invaders. For a while it was successful, and a fishing town grew up around it. Then, three centuries ago the fortress fell to the barbarian raiders and its people slaughtered or enslaved. The raiders made their way inland and continued to be a scourge on the land for another thirty years of bloody war.
Uncivilized barbarians have a way of being infected with the cultures they conquer, however, and as the mix of races developed, one particularly enterprising warlord decided that the island fortress would make a good homeland for his children. The fortress was rebuilt (albeit poorly, at least at first) and he and his people made their home there. His name was Medo, and he renamed the island after himself.
After a time, civilization was once again underway, with Medo recast as a young demigod and the raiders as "the Giants of the North". A pair of centuries passed, and the ways of the former culture continued apace.
A century and a half ago, however, the land shook and the seas boiled. Many believed that Medo had seen the decadence of the modern world and was unhappy with it. These were quickly shushed, and fearful eyes watched the bubbling waters through the night for signs of retribution. None came.
By morning, the seas had stopped boiling, and all was quiet. As the next few days passed, however, boats expected to arrive from the mainland never did. A few boats were sent out, but never returned. And then Medo showed up.
Medo was, in fact, an opportunistic noble of shrewd acumen and a small talent for magick. He had scried elsewhere and learned the situation. He quickly told the city that the gods had in fact destroyed the rest of the world and that the island had been spared in this End of Days because Medo had protected it.
Medo asserted control over the city, and it has become (with the exception of the poor fishermen who feed it) a home to decadence, and quite mad in many ways.