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.