The queen of the Duchy of Beren, Alexandra von Gwendirente, hailed from Strasbourg, a self-governing free city in the Alsace region that belonged to neither Beren nor Roden.
A free city, with no lord and where all citizens are free men, has a unique political structure. I understand there are many such free imperial cities within the Holy Roman Empire.
But as the saying goes, when the cat's away, the mice will play, and powerful families would either form alliances or wage internal struggles to dominate the city. Just like the wealthy farmers of Feuzen who exploited their tenants.
The Gwendirente family was the most influential family in Strasbourg, and the marriage between their daughter and the crown prince of Beren (Karlus) was part of a political strategy to absorb the free city into Beren.
