Battle of Głogów The Battle of Głogów or Defense of Głogów ( , ) was fought on 24 August 1109 at the Silesian town of Głogów , between the Kingdom of Poland and the Holy Roman Empire . Recorded by the medieval chronicler Gallus Anonymus it is presently one of the most well known battles in Polish history . The Polish forces were led by Duke Bolesław III Wrymouth , while the Imperial forces were under command of King Henry V of Germany . Bolesław was victorious . Prelude . After a long - term rivalry within the ruling Piast dynasty , Bolesław III in 1107 had finally expelled his elder half - brother and co - ruler Duke Zbigniew from Poland . Zbigniew fled to the Holy Roman Empire where he sought help from King Henry V . The king however did not take action , as he was stuck in an inner - Hungarian rivalry , supporting the Árpád prince Álmos against his brother King Coloman , and had started an armed expedition to Bratislava ( Pozsony ) . Henry tangled with Bolesław , when the Polish duke , loyal to King Coloman , took the occasion to campaign in the Bohemian lands in 1108 : as soon as the Bohemian duke Svatopluk heard of the invasion , he left the Imperial army to oust the Polish troops . Left alone , King Henry was forced to abandon his Hungarian campaign . Chafing under this defeat , Henry finally associated himself with Zbigniew and requested Bolesław to reinstate his half - brother as co - ruler , well as to pay an annual tribute to the Empire . The Polish duke categorically rejected both demands . 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 ) . At first they defeated a Polish garrison which was stationed near the town , while Bolesław rushed from his battle against the Pomeranians at Nakło . Siege . According to Gallus ' " Gesta principum Polonorum " , King Henry resorted to lay siege to Głogów but granted its citizens a five day ceasefire to ask their king for permission to surrender . He allegedly even made the townsmen give up their children as hostages as a guarantee of the ceasefire and promised to give them back alive no matter what Bolesław ' s answer would be . The Polish duke however had no intention to hand over the city and ordered the defense of Głogów . After the five days were up , King Henry began to barrage the town . 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 . However , Gallus stated that his cruelty towards children only strengthened the resolve of Głogów ' s defenders . Several harsh attacks by the Imperial army were repulsed , while Henry suffered significant losses by Polish guerilla warriors . After many days of unsuccessful fighting , the king was forced to abandon the siege and march south . Aftermath . King Henry ' s campaign turned out to be a complete failure , when it ended in Bolesław ' s final victory at the Battle of Hundsfeld ( " Psie Pole " ) . Duke Svatopluk was assassinated - probably by Bohemian Vršovci liensmen - still at the Głogów camp on September 21 . His successor Vladislaus reconciled with Bolesław , whereafter Zbigniew was able to return to Poland in 1111 , only to be arrested and blinded by his half - brother shortly afterwards . Bolesław ' s position towards the Empire was strengthened , and in the following years he was able to consolidate his rule in Pomerania and Lubusz Land . It was not until 1157 , when Emperor Frederick Barbarossa in aid of the Silesian duke Władysław II the Exile launched a successful campaign to the Polish lands . 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 . A first memorial stone was erected by the Głogów citizens on the occasion of the 850th anniversary of the battle in 1959 . On 1 September 1979 a large Socialist Realistic memorial to the Głogów children was inaugurated to commemorate not only the 870th anniversary but also the 40th memorial day of the German Invasion of Poland .