Nogai Khan
The southern group of Mongol forces under Nogai Khan (divided into at least three detachments) crossed into Poland on December 24, 1287 and besieged Kraków. The Mongols launched an unsuccessful assault on the fortified city, suffering heavy casualties and losing several of their leaders in the process. Nogai Khan decided to change plans, divide his detachment into smaller units, and plunder the areas both north and south of Kraków; his units plundered the villages around Kraków and the Duchy of Sieradz while engaging in small battles with local Polish forces sallying from towns and castles. Parallel to this, two other columns of his army besieged the towns of Podolínec and Stary Sącz. Soon after the battle of Kraków, Leszek, his wife, and a small group of retainers slipped into the Kingdom of Hungary and requested aid from King Ladislaus IV, who had defeated another Mongol invasion less than two years earlier.