Question: Who is John Montagu, 1St Baron Montagu's maternal grandmother?
Sentence (from "John Montagu, 1st Baron Montagu"): Their children included John Montacute, 3rd Earl of Salisbury (– 1400); Eleanor Montacute, who married John Dinham (1359–1428); Thomas Montagu, Dean of Salisbury Cathedral; and Sybil Montagu, Prioress of Amesbury.
Relevant evidence: No