Boleslaw the Chaste or the Shy (Polish Bolesław Wstydliwy) (1226-1279) was the son of Leszek the White. Several years after the death of Henry the Pious at the battle of Legnica (1241), he became king in Kraków, and thereby the predominant prince of the deeply partitioned Poland.

He was married to Kinga or Cunegunda, daughter of the Hungarian king Bela IV. According to medieval chronicles the marriage was never consummated. Kinga, being extremely pious, was averse to fulfilling her marital duties. At first Bolesław tried to convince her to change her mind, but she did not accept. Then he reluctantly accepted the situation. His religious convictions forbade him to take a mistress. That is why he obtained the nick name "the Chaste" or "the Shy".

Under his reign the town of Kraków, destroyed by the Tartars in 1241, was refounded, and mainly settled with German colonists. The new town was built according to a regular chess board pattern (the "location" of 1257).