Question: What is the date of death of Mary Anna Marten's mother?
Sentence (from "Mary Anna Marten"): Mary Anna Sibell Elizabeth Marten, OBE (1929–2010) was born Mary Anna Sibell Elizabeth Sturt on 12 September 1929 at Moor Critchel, the daughter of Napier Sturt, 3rd Baron Alington and Lady Mary Sibell Ashley-Cooper, daughter of the 9th Earl of Shaftesbury, sometime Lord Steward to the Household of George V & Queen Mary, by his wife Lady Constance Sibell Grosvenor (d 1957), a great friend of Queen Mary, dau of Earl Grosvenor, and sister of Hugh Grosvenor, 2nd Duke of Westminster.
Relevant evidence: Yes