In medieval times, an Old Prussian settlement existed at the site under the name of "Mawrin, Maurin" or "Morin". A new town was built on its place by the invading Teutonic Knights after they destroyed the original settlement in the late 13th century. Part of the Order's State, it was given the name "Mohrungen" after a nearby lake and in 1327 attained Kulm town law from the local commander ("Komtur") Hermann von Oettingen. The first inhabitants of the town were emigrants from the southern Harz region in central Germany.