primacy of Prague. Prague was the capital of the Duchy of Bohemia, ruled by Boleslaus II, and the Diocese of Prague was founded there in 973. However, after Adalbert was appointed the head of the Diocese in 982, a conflict escalated between Boleslaus II of Bohemia and Poland's Duke Bolesław I Chrobry in 985, and in 989 Adalbert left the Diocese, only to return in 991 or 992 when a truce was signed. Although he managed to found the Břevnov Monastery, as he was from another principality's noble family, he did not have enough authority and support by Boleslaus II in the Diocese, and in late 994 offered his episcopal see to Strachkvas, Boleslaus II's brother, who nevertheless refused it. In 995 Adalbert again temporarily left for Rome. In these conflicts lies the answer of their downfall. Slavniks did not help Boleslaus II, they were either neutral or allied with Bolesław I of Poland. This was a direct challenge to Boleslaus II; he could not afford any mighty rivals and was determined to add the Slavnik lands to his dukedom. In early September of 995, while Soběslav was at war against Lusatian tribes as Boleslaw's and Otto III's ally, Boleslaus II with confederates (the Vršovci) stormed Libice on September 28, and massacred all of the family, although he originally promised a truce to Soběslav's brothers until his return. Only three Slavnik family members survived, because they were not present at Libice at that time: Soběslav, Adalbert and Radim (Gaudentius). Aftermath Soběslav temporarily lived in Poland and was comforted by Bolesław I. The ruler also stood out as an intermediary for Adalbert toward Boleslaus II, appealing for Adalbert's return, but the nobility and the people did not accept Adalbert, as they were afraid of his possible vengeful intentions. In 996, when Strachkvas Přemyslid was going to assume the office of a bishop in Prague, he suddenly died during the ceremony. The strength of the conflict of the two dynasties is also demonstrated by the Přemyslid rulers' refusal to ransom Saint Adalbert's body from the Prussians who murdered him, so it was purchased by Bolesław I, and was quickly canonized by the common effort with Otto III. Soon after, a temporary anarchy escalated in Bohemia, as two weak dukes Boleslaus III and Vladivoj followed, leading to the Bolesław I's temporary control of Prague. Eventually, a year later, Soběslav was killed by Bohemians