Bolesław II of Masovia or Bolesław II of Płock (pl: Bolesław II mazowiecki (płocki); ca. 1253/58 – 20 April 1313), was a Polish prince, member of the House of Piast, Duke of Masovia during 1262-1275 jointly with his brother, after 1275 sole ruler over Płock, after 1294 ruler over all Masovia and Duke of Kraków and Sandomierz during 1288-1289. In 1310 he gave to his sons the districts of Warsaw and Czersk. Also High duke of Poland twice (1288, 1289).
Władysław I Łokietek, in English known as the "Elbow-high" or Ladislaus the Short (c. 1260/1 – 2 March 1333), was King of Poland from 1320 to 1333, and duke of several of the provinces and principalities in the preceding years. He was a member of the royal Piast dynasty, the son of Duke Casimir I of Kuyavia, and great-grandson of High-Duke Casimir II the Just.
Władysław I inherited a small portion of his father's domain, but his dominion grew as some of his brothers died young. He unsuccessfully tried to incorporate the Duchy of Kraków (the Seniorate Province) in 1289, following the death of his half-brother Leszek II the Black and the withdrawal from contention of his ally Bolesław II of Masovia. After a period in exile during the rule of Wenceslaus II, Władysław regained several duchies and then Kraków in 1306 when Wenceslaus III was murdered. He temporarily took control of part of Greater Poland after the death of his ally Przemysł II, lost it, and then regained it.