The Peace of Bautzen (German: Frieden von Bautzen; Polish: Pokój w Budziszynie; Upper Sorbian: Budyski měr) was a treaty concluded on 30 January 1018, between Holy Roman Emperor Henry II and Bolesław I of Poland which ended a series of Polish-German wars over the control of Lusatia and Upper Lusatia (Milzenerland or Milsko, the eastern part of the margraviate of Meissen (Miśnia)) as well as Bohemia, Moravia and Slovakia.

In the ensuing struggle Bolesław allied himself with the Holy Roman Empire's noble opposition to Henry, while the emperor sought support among the Lutici, a Slavic pagan Polabian tribe.

An intermediate peace was concluded in Merseburg in 1013 which preserved the territorial status quo, with Bolesław holding on to Moravia and Slovakia, while Jaromir was made the ruler of Bohemia (though he was soon deposed by his brother Oldrich).

Henry II was however unable to defeat Bolesław I, and agreed on a peace in Bautzen (1018) which left the Duke of Poland in charge of the Lusatian march and Upper Lusatia.

The emperor also promised to aid Bolesław in his intervention in the Kievan succession crisis in the summer of 1018 with contingents of German and Hungarian troops which enabled the Polish ruler to capture Kiev and reclaim the previously lost Cherven Cities.

After the death of emperor Otto III, Bavarian duke Henry IV and Meissen margrave Eckard (Ekkehard) I competed for succession.

Bolesław however avoided an open battle, harried the emperor's troops with guerrilla tactics and caused "great losses", according to contemporary German chroniclers.

[13] The fighting was concluded in 1005[12] when Tagino, Archbishop of Magdeburg mediated a peace near Poznań,[10] as a result of which Poland had to give up Lusatia and Meissen but kept Slovakia and Moravia for the time being.

[10] During this campaign, which started in Belgern, Henry II was struck by an illness at Jarina castle and returned with some of his bishops, while the remaining armies devastated the surrounding area.

[15] Henry II started his Italian campaign in the fall of 1013, defeated the allies of the Crescentians and had pope Benedict VIII crown him Holy Roman Emperor in Rome on 14 February 1014.

During the fighting Margrave Gero, as well as two hundred other German knights were killed by Polish bowmen and Bolesław allowed the Bishop of Meissen, Eido, to recover the bodies for burial.

The contemporary German chronicler Thietmar of Merseburg, generally ill-disposed towards Poles, on this occasion commented on the bravery and skill of the defenders, noting that they neither cheered when they were successful, nor lamented when they suffered a setback.

[17] Eventually, due to an illness of part of his army Henry aborted the siege and withdrew, taking the route to Bohemia because the way back into Germany was blocked by Boleslaw's main forces, stationed at Wrocław.

[18] The contemporary German chronicler Thietmar, who was generally ill-disposed towards Poles,[19] commented on the peace with the words "non ut decuit sed sicut fieri potuit", meaning "not as it should have been but as was possible in the circumstances".