German–Polish War (1002–18)

The German–Polish War which took place from 1002 to 1018 consisted of a series of struggles between the Ottonian Henry II (first as King of Germany and then Holy Roman Emperor) and the Polish Piast ruler Boleslaw Chrobry. The locus of conflict was the control of Lusatia, Upper Lusatia, as well as Bohemia, Moravia and Slovakia. The fighting ended with the Peace of Bautzen in 1018, which left Lusatia and Upper Lusatia with Poland, but Bohemia became a duchy in the Holy Roman Empire.

1002–1005
In 1002, after the conclusion of a council at Merseburg an attempt was made on Boleslaw's life, which he escaped with the help of several friendly German nobles. While it is not known for sure if the attack had been ordered by Henry, Boleslaw believed this was the case. Henry II did neither protect him, nor punish the assailants. The fighting began in late 1002 and did not stop until a peace was agreed to at Poznan in 1005, as a result of which Boleslaw had to give up his earlier conquests of Lusatia and Meissen.

1007–1013
In 1007, Boleslaw, most likely preempting an attack by Henry, once again took control of Lusatia and Meissen. After several unsuccessful campaigns by Henry another peace was agreed to in Merseburg in 1013. This time Boleslaw kept Lusatia and Meissen as imperial fiefs and received aid from Henry for his expedition to the Kievan Rus. In return, Boleslaw promised to support Henry's bid for the crown of Holy Roman Emperor and aid him in his Italian campaigns.

1015–1018
After Merseburg, Boleslaw failed to support Henry in Italy and also refused to acknowledge Meissen and Lusatia as fiefs; he believed he held them independently of the empire. As a result in 1015 Henry, supported by pagan Lutician allies, launched an armed expedition against him.

In 1015 Henry attempted to cross into Wielkopolska but was stopped by Boleslaw's troops at Krosno on the Oder. In 1017 Henry renewed his campaign and besieged Niemcza. With the help of outside reinforcements however the city held out and Henry was eventually forced to retreat.

In January 1018 a peace treaty was concluded at Bautzen, which left Lusatia and Upper Lusatia with Boleslaw. Contemporary chronicle of Thietmar of Merseburg does not give details of the treaty. Historians have differed in their interpretation whether these were granted to Boleslaw as imperial fiefs, or if he held them with full sovereignty. Henry II did not renew the campaigns against Boleslaw I thereafter and the peace was confirmed by the marriage of Oda of Meissen, daughter of Eckard I, to Boleslaw.