Question: What is the date of death of Soběslav (Died 1004)'s mother?
Sentence (from "Soběslav (died 1004)"): Soběslav or Soběbor (c. 950 – 1004) was the brother of Saint Adalbert of Prague, son of Střezislava and Slavník and a friend of Polish king, Boleslaus the Brave.
Relevant evidence: Yes