Premise: Fanny Talbot (née) Browne (1824–1917) was a landowner and philanthropist, and a friend and correspondent of the influential art critic John Ruskin. She is noted for donating the first property—4.5 acres of land known as Cliff of Light ("Dinas Oleu" in Welsh), at Barmouth, Gwynedd—to the National Trust.
Hypothesis: Fanny Talbot donated the largest piece of land to the National Trust.