Second Mongol invasion of Poland The second Mongol invasion of Poland was carried out by general Boroldai ( Burundai ) in 1259 - 1260 . During this invasion the cities of Sandomierz , Krakow , Lublin , Zawichost , and Bytom were sacked by Mongols for the second time . The invasion began in late 1259 , after a powerful Mongol army had been sent to the Kingdom of Galicia – Volhynia in order to punish King Daniel of Galicia for his independent actions . King Daniel had to comply to Mongol demands , and in 1258 , his forces joined the Mongols in the raid on the Grand Duchy of Lithuania . To weaken Daniel ’ s position , the Golden Horde decided to attack his allies , Hungarian King Bela IV , and Duke of Krakow , Boleslaw V the Chaste . The purpose of the invasion was to loot the divided Kingdom of Poland ( see Testament of Boleslaw III Krzywousty ) , and to weaken Duke of Krakow Boleslaw V the Chaste , whose province , Lesser Poland , began a process of fast development . According to the Mongol plan , the invaders were to enter Lesser Poland east of Lublin , and head towards Zawichost . After crossing the Vistula , the Mongol army was to break into two columns , operating north and south of the Holy Cross Mountains . The columns were to unite near Checiny , and then head southwards , to Krakow . Altogether , Mongol forces under Boroldai were 30 , 000 strong , with Ruthenian units of King Daniel , Kipchaks and probably Lithuanians or Yotvingians . The events that took place in the Kingdom of Galicia – Volhynia echoed in Lesser Poland , and in late 1258 , preparations for the defence of Krakow began . The work was quickly abandoned , and Piast dynasty dukes returned to their internal quarrels . In October 1259 , right before the invasion , Duke of Greater Poland Boleslaw the Pious allied himself with Duke Boleslaw V the Chaste and Duke of Mazovia Siemowit I , in order to attack Duke of Kujawy , Casimir I of Kuyavia . A few weeks later , Lesser Poland was invaded by the Asiatic hordes . Mongolian army concentrated near Chelm , and after capturing Polish towns east of the Vistula , the invaders appeared at Sandomierz ( early December 1259 ) . Boroldai ordered Ruthenian auxiliary units to besiege and capture the city , while main Mongol forces marched westwards , to the Holy Cross Mountains . Their march was marked by an orgy of destruction ; among others , ancient abbeys of Koprzywnica and Wachock were looted ( most probably , they failed to capture the Lysa Gora Benedictine Abbey ) . The Mongols limited their advance to Radom in the north and Sulejow in the west , and did not enter other Polish provinces . The two columns of the invading army joined forces near Kielce and Checiny , in mid - January 1260 . At the same time , the siege of Sandomierz continued . Defenders of the city fiercely resisted all attacks of the Mongol and Ruthenian forces . After several weeks , Mongol leaders began negotiations with the Poles , who were commanded by a man named Piotr of Krepa . Ruthenian princes , which took part in the siege , advised Piotr of Krepa to accept Mongol offer , and abandon Sandomierz , in exchange of safe passage for all residents of the city . Finally , facing hunger and epidemics , Poles and left Sandomierz on February 2 , 1260 . The Mongols , as predicted , broke their promises , and massacred the civilians and the defenders . The city itself was looted and burned to the ground . On February 5 , main Mongol forces abandoned Sandomierz . All units joined forces on February 10 – 12 , and entered densely populated southern Lesser Poland . After looting the abbeys at Jedrzejow , Mogila , Szczyrzyc and Miechow , the invaders flooded the region , in an orgy of murder and destruction . In the second half of February , the Mongols reached Krakow , quickly capturing the city , but without the Wawel Hill , which was fortified and defended . To prevent Silesian Piast dukes from sending their support to Lesser Poland , Boroldai sent some units to the area of Bytom . Duke Boleslaw V the Chaste himself fled to Sieradz , with his wife Kinga of Poland . In late March 1260 , the Mongols left Lesser Poland , along the Carpathian foothills . The province that they had invaded was completely destroyed , with rich looty some 10 , 000 Poles taken with the invaders as slaves . The success of the Golden Horde was complete , as they managed to destroy an anti - Mongol alliance , and completely subjugate Kingdom of Galicia – Volhynia .