Question: What nationality is Stephen Ii, Duke Of Bavaria's mother?
Sentence (from "Beatrice of Silesia"): Beatrice of Silesia (also known as Beatrice of Świdnica; , ; 1290 – 25 August 1320) was a Polish princess member of the House of Piast in the Silesian branch of Jawor-Świdnica and by marriage Duchess of Bavaria and German Queen.
Relevant evidence: Yes