Leszek II the Black
Radomsko dates back to the 11th century. The oldest known mention of Radomsko comes from a document of Konrad I of Masovia from 1243. It received town privileges from Duke Leszek II the Black of Sieradz in 1266. During the times of fragmentation of Piast-ruled Poland, it was part of the Seniorate Province and Duchy of Sieradz, and afterwards it was a royal town of the Polish Crown, administratively located in the Sieradz Voivodeship in the Greater Poland Province of the Polish Crown. In 1288, Duke Leszek II the Black brought Franciscans to the town, and in 1328, King Ladislaus the Short funded the construction of the Gothic Franciscan church.