Ottonian–Polish relations Bolesław maintained good relations with Emperor
Otto III (): together they fought against the West Slavic
Lutici tribes and the
Obotrites. The Ottonian emperors had also supported Polish expansion against the
Přemyslids, in the Baltic areas and against
Kyivan Rus' since the 970s. The Polish ruler also allied with Margrave
Eckard of Meissen to contain the influence of the Přemyslid dukes of
Bohemia. In 1000 Bolesław and Otto met at the
Congress of Gniezno and solemnly celebrated their mutual recognition and friendship, with Bolesław called 'brother and cooperator of the [Holy Roman] Empire, friend and ally of the Roman people'.
German succession crisis (January–October 1002) The circumstances changed significantly, when in January 1002 Emperor Otto III suddenly died at the age of 21, leaving no heirs nor any succession arrangements. The
Bavarian duke Henry IV, member of a cadet branch of the Ottonian dynasty, raised claims to become
King of the Romans – against rivalling duke
Herman II of Swabia and margrave
Eckard of Meissen. The latter was attacked and killed by
Saxon nobles a few weeks after. Henry was
elected and crowned king in
Mainz on 6 or 7 June 1002. Henry then launched an indecisive campaign against Herman of Swabia, but was recognised by the Thuringians, Saxons and lower Lotharingians in subsequent months, either by homage or renewed election. Herman of Swabia eventually submitted to king-elect Henry II on 1 October 1002.
Merseburg council (July 1002) Bolesław occupied Lower Lusatia and the Milsko/Milzener land around Budziszyn (now
Bautzen), advancing further to the west across the Elba river and taking
Meissen (), with the neighboring
Sorbian regions up to
White Elster river. Those gains were achieved after the death of Eckard, presumably in agreement with the Ekkehardings, and when Bolesław participated in the renewed election of Henry II by the Saxon princes on July 1002 at the in
Merseburg, Henry gave Bolesław eastern portions of those lands (Lusatia and Milsko) as fiefs. In return, Bolesław recognised Henry as king. Bolesław's claims for enfeoffment of Meissen were rejected; these passed on to Eckard's brother
Gunzelin, Margrave of Meissen. Bolesław left the royal court with disappointment. Moreover, an attempt was made on Bolesław's life, which he escaped only with the help of Duke
Bernard of Saxony, the
Nordgau margrave
Henry of Schweinfurt and several friendly German nobles. While it is not known for sure if the attack had been ordered by Henry and the contemporary chronicler
Thietmar of Merseburg denied any complicity, Bolesław believed this was the case. In any case Henry neither protected him, nor punished the assailants.
Meissen inheritance struggle (1002) Thietmar of Merseburg reported in his
Chronicon that Bolesław set
Strehla Castle in the Margraviate of Meissen ablaze on his way back to Poland, although it remains unclear why he did so. At the time, the castle town of Strehla (Polish:
Strzała) was in the possession of
Regelinda, the new wife of
Herman I, Margrave of Meissen, the oldest son of Eckard. Although Gunzelin had received his older brother Eckard's inheritance according to the principle of
agnatic seniority – then still 'commonly respected among Slavic communities of the period' – Herman at the Merseburg council also seems to have pressed rights to his father's inheritance according to the newly emerging principle of
agnatic primogeniture as Eckhard's firstborn son. Thietmar also suggested that Herman was involved in the attempt on Bolesław's life, and that this was the reason why the Piast duke razed Strehla, the castle town owned by Herman's wife. Herman would eventually lose the Meissen inheritance struggle against his uncle Gunzelin, who was supported by Bolesław. The Piast ruler himself referred to both his former marriage with a daughter of the earlier deceased margrave
Rikdag and his present marriage with
Emnilda, daughter of a Lutici prince, in order to expand his influence to the
Lusatian and Meissen
marches. King Henry in turn renewed his Bavarian fellowship with the Přemyslid rulers of Bohemia, old-time enemies of the Polish Piast dynasty.
Bohemian war of succession (since 999) After the death of duke
Boleslaus II "the Pious" of
Bohemia, a fratricidal war erupted between his three sons
Boleslaus III,
Jaromír, and
Oldřich. Boleslaus III initially managed to secure the throne and expel his brothers and mother Emma, who in 1001 took refuge at the court of duke Henry IV of Bavaria (who became the German king Henry II 3 years later), but bishop Thiedag (Thiddag) of Prague and part of the nobility still opposed him. Although Thiedag fled to
Eckard I, Margrave of Meissen, the hostile nobles deposed Boleslaus III and instead enthroned
Vladivoj in May 1002. Vladivoj paid homage to German king Henry II as Bohemia's overlord, but was unable to re-establish order to Bohemia during his brief reign (he died in January 1003). After his death, the Bohemian nobles invited Jaromír and Oldřich back from exile in Bavaria to take the throne. But then the Polish duke
Bolesław I the Brave intervened by militarily invading and occupying Bohemia, and putting Boleslaus III (who had been in his custody) back in power as his vassal. Boleslaus III took bloody revenge on many nobles who had deposed him, especially the
Vršovci clan, so that Bohemian opinion turned against him. Then Bolesław of Poland imprisoned and blinded Boleslaus III, and assumed personal rule over Bohemia. ==Conflict==