The Teutonic Knights could not pay their mercenaries, so the mercenaries sold the Order's capital, Marienburg, to the King of Poland in 1457

Marienburg on the Nogat became the seat of the Teutonic Order on 14 September 1309, when Grand Master Siegfried von Feuchtwangen moved there. Ludwig von Erlichshausen was elected Grand Master on 21 March 1450. The towns and nobles of the Prussian League allied with the King of Poland and declared war on the Order on 4 February 1454. Most of the Order's castles fell. Mercenaries from Germany and Bohemia came to relieve Marienburg, and in September 1454 they beat the Polish army at Konitz. The Order had no money to pay them. Ludwig pawned Marienburg and other castles to the mercenaries. He could not redeem them. In June 1457 the Bohemian mercenaries sold Marienburg to King Casimir IV, who raised the money mainly through Danzig. Ludwig had secretly moved most of the archives to Tapiau. He was held almost as a prisoner, taken to Konitz, and escaped to Königsberg, which became the Order's seat. The mercenaries were later condemned for an unlawful sale, but the castle stayed Polish. By the Second Peace of Thorn in October 1466 the Order lost Pomerelia, Kulm, Marienburg and Elbing, and Ludwig swore a personal oath of loyalty to the king. He died in Königsberg on 4 April 1467. Under Polish rule the castle held salt, beer and a garrison. It was heavily damaged in 1945. It has been a museum since 1961.