as well as against the Reginarids in Lotharingia. However, this Ottonian hegemony was personalistic rather than institutional, and quickly disappeared after the accession of Hugh Capet in 987. Burgundy Otto continued the peaceful relationship between Germany and the Kingdom of Burgundy initiated by his father. King Rudolf II of Burgundy had previously married Bertha of Swabia, the daughter of one of Henry's chief advisers, in 922. Burgundy was originally a part of Middle Francia, the central portion of Charlemagne's empire prior to its division under the Treaty of Verdun in 843. On 11 July 937, Rudolf II died and Hugh of Provence, the King of Italy and Rudolf II's chief domestic opponent, claimed the Burgundian throne. Otto intervened in the succession and with his support, Rudolf II's son, Conrad of Burgundy, was able to secure the throne. Burgundy had become an integral, but formally independent, part of Otto's sphere of influence and remained at peace with Germany during his reign. Bohemia Boleslaus I, Duke of Bohemia, assumed the Bohemian throne in 935. The next year, following the death of Otto's father, King Henry the Fowler, Boleslaus stopped paying tribute to the German Kingdom (East Francia) in violation of the peace treaty Henry had established with Boleslaus' brother and predecessor, Wenceslaus I. Boleslaus attacked an ally of the Saxons in northwest Bohemia in 936 and defeated two of Otto's armies from Thuringia and Merseburg. After this initial large-scale invasion of Bohemia, hostilities were pursued, mainly in the form of border raids. The war was not concluded until 950, when Otto besieged a castle owned by Boleslaus' son. Boleslaus decided to sign a peace treaty, promising to resume payment of tribute. Boleslaus became Otto's ally, and his Bohemian force helped the German army against the common Magyar threat at the Lech river in 955. Later he went on to crush an uprising of two Slavic dukes (Stoigniew and Nako) in Mecklenburg, probably to ensure the spread of Bohemian estates to the east. Byzantine Empire During his early reign, Otto fostered close relations with Emperor Constantine VII Porphyrogenitus, who ruled over the Byzantine Empire from 913 until his death in 959; East Francia and Byzantium sent several ambassadors to one another. Bishop Thietmar of Merseburg, a medieval chronicler, records: "After this [Gilbert's defeat in 939], legates from the Greeks [Byzantines] twice brought gifts from their emperor to our king, both rulers being in