Kaliningrad (Russian: Калининград, German: Königsberg) is a seaport and the administrative center of Kaliningrad Oblast, the Russian exclave between Poland and Lithuania on the Baltic Sea. The territory is geographically separated from the rest of Russia. Originally named Königsberg, the Prussian and German town had been founded in 1255, and was then largely destroyed during World War II. Its ruins were occupied by the Soviet Army in 1945 and it was renamed Kaliningrad in 1946. In the meantime, the name was briefly Russified as Kyonigsberg (Кёнигсберг). The castle of Königsberg was built in 1255 by the Teutonic Knights. Königsberg became a centre of education when Albertina University was founded by Duke Albert of Prussia in 1544. Notable resident Immanuel Kant (1724-1804), philosopher