In the Middle Ages, Nowy Korczyn was a trade village, located on a junction of busy merchant roads from Kraków to Kievan Rus', and from Kosice to Sandomierz. To distinguish it from the nearby village of Korczyn (now known as "Stary Korczyn", "Old Korczyn"), Prince Boleslaus V the Chaste named the town "Nowe Miasto Korczyn" ("New Town Korczyn"), when he granted it Magdeburg rights (1258). In 1257, when the Prince stayed here with his wife Kinga of Poland, the pious couple decided to found a Franciscan abbey in Nowy Korczyn. The town quickly developed, due to its location, and proximity both to the Vistula waterway and the city of Kraków, where local princes resided during the fragmentation of Poland (see History of Poland during the Piast dynasty). It had a wooden castle, which, together with the town, was burned by the Rus warriors in 1300. New, stone castle was built here in the 1350s by King Kazimierz Wielki, and it quickly emerged as one of the major royal residences in Poland. A defensive wall was built around Nowy Korczyn, furthermore the town was protected by a man-made lake "Czartoria".