Question: When did Peter Antonovich Of Brunswick's mother die?
Sentence (from "Anna Leopoldovna"): Anna Leopoldovna (18 December 1718 – 19 March 1746), born Elisabeth Katharina Christine von Mecklenburg-Schwerin and also known as Anna Carlovna (А́нна Ка́рловна), was regent of Russia for a few months in 1740 and 1741 during the minority of her infant son Emperor Ivan VI.
Relevant evidence: Yes