Question: What is the date of death of Hedvig Elizabeth Von Biron's mother?
Sentence (from "Hedvig Elizabeth von Biron"): Hedvig Elizabeth von Biron of Courland( 1727–1797), was a princess of Courland and a Russian courtier, daughter of the Duke of Courland, Ernst Johann von Biron, and Benigna Gottlieb von Trotha gt Treyden, and the sister of Peter von Biron.
Relevant evidence: Yes