Ozyorsk (, until 1938 ; ; ; from 1938 to 1946 ) is a town and the administrative center of Ozyorsky District in Kaliningrad Oblast, Russia, located on the Angrapa River near the border with the Polish Warmian-Masurian Voivodeship, southeast of Kaliningrad, the administrative center of the oblast. Population: History Before the arrival of the Teutonic Order, the river valley was here settled by the Nadruvians, as evidenced by traces of settlements and fortifications found in the area. Teutonic overlordship was established around 1388, but the town is mentioned for the first time in written sources in 1539 as Darkyem. In 1454, the region was incorporated by King Casimir IV Jagiellon to the Kingdom of Poland upon the request of the anti-Teutonic Prussian Confederation. After the subsequent Thirteen Years' War, since 1466, it formed part of Poland as a fief held by the Teutonic Order, and after 1525 it was located in Ducal Prussia, a vassal duchy of Poland. It was settled by Lithuanian, Polish and German colonists. A first church was built in 1615. From 1701, it formed part of the Kingdom of Prussia. The settlement remained a village until 1724, when it received city rights by Frederick William I of Prussia. Soon afterwards, the town plan was revised with a market square and a new grid plan. An influx of immigrants followed (in 1725, 103 of the 742 registered inhabitants came from Salzburg) and craft production of leather and cloth established in the town. In the 19th century the industry had to close due to competition from more efficient industries in western Germany. Nine annual fairs were organized in the town in the late 19th century. Due to its location on the Angrapa River, a power station established in the watermill was already in 1880 able to produce electrical light for the town. The town was heavily damaged during fighting in World War I but rebuilt after garden city ideals following the war, with financial support from the city of Dresden. From 1871 to 1945 the town was part of Germany, within which it was administratively located in the province of East Prussia. Two labour camps of the Reich Labour Service were operated in the town under Nazi Germany. It was captured by the 3rd Belorussian Front of the Red Army on 23 January 1945 in the course of the East Prussian offensive. After Germany's defeat in World