Question: What is the date of death of Stanisław Radziwiłł's mother?
Sentence (from "Stanisław Radziwiłł"): Stanisław "the Pious" Radziwiłł  (May 12, 1559 – March 19, 1599) was a sixth generation Radziwill family noble (szlachcic) of the Grand Duchy of Lithuania in the Polish-Lithuanian Commonwealth.
Relevant evidence: No