The eldest son of DukeBoleslaus II "the Pious", probably with his first wifeAdiva, he succeeded to theBohemian throne upon the death of his father in 999. Boleslaus III turned out to be a weak ruler and soon entered into a fierce inheritance conflict with his younger brothersJaromír andOldřich. He had both expelled to theBavarian court ofHenry II inRegensburg, together with their mother Dowager DuchessEmma.
By 1002, a revolt organized by nobles of the rivalVršovci clan (along with Boleslaus's son-in-law) forced him to flee to Germany, where he was received by MargraveHenry I of Austria. At first, Henry I ordered the arrest of his guest because of an old offence, but soon forgave him and promised support. Meanwhile, thePolish dukeBolesław I installed Boleslaus' kinsmanVladivoj on the Bohemian throne. Vladivoj was apparently an alcoholic, however, and died within a year. After the death of Vladivoj in 1003, the Bohemian nobles invited Jaromír and Oldřich back from exile. In turn, they each later assumed the throne atPrague.
On 9 February 1003, Boleslaus the Red was restored to authority with armed support from Duke Bolesław of Poland. Boleslaus's brothers Jaromír and Oldřich again fled to Germany and placed themselves under the protection of Henry II. But Boleslaus soon undermined his own position by ordering a massacre of the nobles of the Vršovci clan atVyšehrad. According to the chroniclerThietmar of Merseburg, Boleslav slashed his son-in-law to death with his own sword.
Nobles who survived the massacre secretly sent messengers to Bolesław the Brave of Poland and entreated him to save them. The Polish duke willingly agreed and invited his Czech namesake to visit him at his castle (probably inKraków). There, Boleslaus the Red was trapped, blinded and imprisoned. He never returned to Bohemia. Bolesław the Brave claimed the ducal throne for himself, invaded Bohemia in 1003 and tookPrague without any serious opposition; he ruled as Duke Boleslaus IV for a little over a year. He then gave up his claim to the duchy of Bohemia and was replaced by Jaromír, who, backed by Henry II, entered through the Prague gates and in 1004 received the Bohemian duchy as a fief from the hands of the German king.
