,Boleslav I the Cruel of Bohemia, Duke of Bohemia acceeded 929 , died 972.
His father was
Vratislav I of Bohemia, Duke of Bohemia.
,Boleslav I had a brother named [Boleslaw II the Pious]
? of Bohemia, Duke of Bohemia born abt. 920 , and a sister named Dobravy of Bohemia aka
Dubrawka von Boehmen.
the , indicates , that he was known by another name.