Question: What is the date of birth of Prince Oskar Of Prussia's mother?
Sentence (from "Ernst-Johann Biron, Prince of Courland"): He was born in Berlin, the eldest son of Karl, Prince Biron of Courland( 1907- 1982), and Princess Herzeleide of Prussia( 1918- 1989), the daughter of Prince Oskar of Prussia( a son of Emperor William II) and Augusta Viktoria of Schleswig- Holstein.
Relevant evidence: No