The Tale of the Marches
As the Old Man tells it
An old man travels from inn to inn telling a story, and he tells it a bit differently every time depending on who's listening. It's about Statio Memoria, a city nobody alive has seen, and the wild country across the river from it called the Marches.
The Crown started handing out charters, so anyone who crossed the river could claim land in the Marches and keep it as long as they could hold onto it. All sorts of people went. Some built halls and got rich, some lost everything, and most of them spent a lot of time arguing with their neighbours over borders.
That was a very long time ago, and plenty of people think it never happened. Farmers still dig up old coins with a crown on them that nobody recognises, though, and the old man is still telling the story.