The town was developed at the site of a former Baltic Prussian settlement named Susse, from which comes the town's Polish name Susz. Throughout its history the town carried a rose in its coat of arms (in German Rosenberg means "rose hill"). In 1454, King Casimir IV Jagiellon incorporated the town and the surrounding region to the Kingdom of Poland upon the request of the Prussian Confederation, and, after the subsequent Thirteen Years' War, from 1466 it was part of Poland as a fiefdom held by the Teutonic Order,Górski, p. 96–97, 214–215 which in 1525 was secularized as the Duchy of Prussia. From the 18th century the town, known in German as Rosenberg, was part of the Kingdom of Prussia, and between 1871 and 1945, it was part of the German Reich.
