WIKIPEDIA:

“ Fanny Mendelssohn (14 November 1805 – 14 May 1847), later Fanny [Cäcilie] Mendelssohn Bartholdy and, after her marriage, Fanny Hensel, was a German pianist and composer, the sister of the composer Felix Mendelssohn and granddaughter of the philosopher Moses Mendelssohn. She was the grandmother of the philosopher Paul Hensel and the mathematician Kurt Hensel.

Life
Mendelssohn was born in Hamburg, the oldest of four children. She was descended on both sides from distinguished Jewish families; her parents were Abraham Mendelssohn (who was the son of philosopher Moses Mendelssohn and later changed the family surname to Mendelssohn Bartholdy), and Lea, née Salomon, a granddaughter of the entrepreneur Daniel Itzig. She was not however brought up as Jewish, and never practised Judaism, though it has been suggested that she "retained the cultural values of liberal Judaism".
Fanny shared the early musical education and upbringing of her younger brother Felix, including tuition from Carl Friedrich Zelter and others. Zelter indeed at one point favoured Fanny over Felix: he wrote to Goethe in 1816, in a letter introducing Abraham Mendelssohn to the poet, 'He has adorable children and his oldest daughter could give you something of Sebastian Bach. This child is really something special'. [......] ”

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