In the beginning, Rosent wasn't a place name. It was originally the name of a weak noble family that had lived in the northern region before the Moel Empire was founded.
However, after that weak noble family named Rosent opted to fight in the war to unite the continent alongside the Great Emperor Graham, who was still the King of a small country at the time, the weak noble family named Rosent ultimately achieved great glory as one of the Moel Empire's founding families.
Just as the first patriarch of the Berdandy family decided to guard the western border region with the title of Marquess rather than living in the capital with Emperor Graham as a Duke, the Rosent family preferred to settle in its previous domain in the north rather than mingling with the nobles in the Imperial capital.