A little bit of history…
  After capturing and plundering the south and north-east of ancient Russia Tatar-Mongol troops headed for the west. European rulers hurriedly gathered their troops and took measures to withstand the enemy’s force.
  The first country on the way of Tatar-Mongols was Poland. In winter 1241 their troops invaded the southern part of Poland, reducing to ashes the cities Sandomir and Krakow. Then Tatar-Mongol army splitted into two parts - the biggest one went to Hungary across the Carpathians, another one went to the north, to the northern regions of Poland.
  Duke Henry II of Silesia, also known as Henry the Pious, was gathering forces to give the decisive battle in Low Silesia. King Wenceslas I of Bohemia moved his troops to the Silesian border, intending to join Henry’s army. However this intention was not realizes.
  Meanwhile, Tatar-Mongols were rapidly moving towards Liegnitz, one of the Silesian cities. Having crossed the river Oder, they captured Wroclav. A week later, on the 9th of April 1241, near Liegnitz, Henry, who could not wait for Bohemian reinforcement any longer, started the battle, which ended with the total defeat of the Polish army. The Polish Duke himself was killed and beheaded.

Hic fertur caput eiusdem ducis henrici filii sancte hedwigis in lancea a thartaris ante castrum legnicz.