The Chronica Boemorum names "secundus Bolezlaus dux" as son of Boleslav. His birth date range is estimated from the birth date of his younger brother, and assuming that the birth date range of their father is accurate.
He succeeded his father in [967] as BOLESLAV II "der Fromme" Duke of the Bohemians. Duke Boleslav supported the rebellion of Heinrich II "der Zänker" Duke of Bavaria against his cousin Emperor Otto II in [974/75]. After the latter confiscated the duke's territories, ex-Duke Heinrich fled to Bohemia and took refuge with Duke Boleslav.... Duke Boleslav supported Heinrich "den Zänker" ex-Duke of Bavaria in his rebellion against Otto III King of Germany in 984. He founded Lundenburg abbey in 993.
The Cronica Principum Regni Boemiæ records the death in 999 of "Boleslaus Pius filius Boleslai Sacui", adding that he created the bishopric of Prague and founded the monasteries of "sanctum Georgium et in Breunowia et in Insula". 1
Research Notes: