The Mongols invaded Poland in late 1240, and were advancing westwards; they crossed the frozen Vistula river and defeated the Poles in Tursko and Sandomierz on February 13, 1241.
[1] Then, the Mongol forces split into two or three armies, with the main one led by Baidar heading towards Kraków (Cracow), a large city (and capital of the fragmented Polish Kingdom) in central-southern Poland.
[6] Bolesław's escape damaged the morale of the army, and caused many others to withdraw as well, weakening the forces available to Włodzimierz and Pakosław.
[6] While the Polish forces had the advantage in the first phase of the battle, the Mongols, seeing that they would not defeat the Poles in straight combat, feigned a retreat.
[5] Polish casualties were very heavy (Norman Davies wrote: "At Chmielnik, the assembled nobility of Malopolska perished to a man"[7]); Włodzimierz and Pakosław were slain, as were Castellan of Kraków Klement of Brzeźnica and Castellan of Sandormierz Jakub Raciborowicz.