Henry V, Zbigniew and Bohemian Duke Svatopluk set out on an armed expedition into Poland, where they besieged the border town of Głogów, which they failed to conquer, but were also defeated in the Battle of Hundsfeld.

The next year, the German forces gathered at Erfurt, crossed the Polish border near Krosno on the Bóbr River, and on St. Bartholomew's Day approached the fortified town of Głogów (Svatopluk's troops arrived in September).

Breaking his promise, he chained the child hostages to his siege engines, hoping that the people of Głogów would not shoot their own offspring, which would allow him to conquer the Polish settlement.

[2] According to Wincenty Kadłubek, the Germans were ambushed by the Polish forces and the result was a complete victory of Bolesław III Wrymouth, whereafter King Henry withdrew from Poland.

After the encounter, due to the many dead and dying left on the battlefield; Kadłubek remarked, that the "...dogs which, devouring so many corpses, fell into a mad ferocity, so that no one dared venture there."

Present-day historians are split on the issue, with some arguing that the battle was rather an unimportant skirmish, and the Chronica, written at the court of Bolesław's son Casimir II the Just almost hundred years after the event, is not fully reliable.

After centuries-long ambivalent relations with Germany, the successful defense and the tradition of Henry's cruelty had evolved to a key element in the memory of the Polish nation.