In the 15th century, several important meetings and events took place at the Nowy Korczyn castle. In 1461, King [[Casimir IV Jagiellon]] hosted here envoys of [[George of Poděbrady]], the [[Crimean Khanate]], and the [[Margraviate of Brandenburg]], and in 1465, szlachta of both Lesser and [[Greater Poland]] gathered here to discuss finances needed to end the [[Thirteen Years' War (1454–66)|]]. In 1470, Casimir IV Jagiellon met at the Nowy Korczyn castle with [[papal legate]] and envoy of Emperor [[Frederick III, Holy Roman Emperor|]]. On October 9, 1479, [[Martin Truchsess von Wetzhausen]], [[...|Grand Master of the Teutonic Knights]] paid [[homage]] to the Polish king at Nowy Korczyn.
In the [[Kingdom of Poland (1385–1569)|]], Nowy Korczyn was one of the most important administrative centers of the vast province of Lesser Poland. Here Lesser Poland [[sejmik]]s took place, in which regional senators and deputies of the [[Sejm]] met to discuss and coordinate their policies. The Nowy Korczyn sejmiks included representatives from [[Kraków Voivodeship]], [[Sandomierz Voivodeship]], [[Lublin Voivodeship]], [[Podole Voivodeship]], and . Furthermore, the town was the seat of a [[starosta]] (one of six starostas of Sandomierz Voivodeship), and the seat of court for the [[Wiślica]] and [[Pilzno]] counties.