Question: Who is the paternal grandfather of Purnima Devi?
Sentence (from "Hemendranath Tagore"): Hemendranath Tagore (1844–1884), Debendranath Tagore's third son, is notable for being the first Brahmo as the first child born in 1844 to any of the original 21 Brahmos who swore the First Brahmo Covenant on 21 December 1843 at Calcutta (now Kolkata).
Relevant evidence: Yes