 Bolesław IV wanted to take advantage of this situation and shortly after he captured the district of Podlachia.The Lithuanians threatened Boleslaw with war, because the previous agreement between King Władysław II and Janusz I only granted the land during the latter's lifetime.In 1444 began the Lithuanian–Masovian War for the possession of Podlachia; following Casimir's orders, the voivode Jonas Goštautas captured Mielnik and Drohiczyn.