Fanny Cäcilie Mendelssohn (14 November 1805 – 14 May 1847), later 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.
Fanny 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 Moses Mendelssohn and later changed the family surname to Mendelssohn Bartholdy), and Lea, née Salomon, a granddaughter of the entrepreneur Daniel Itzig.
Fanny benefited from the same musical education and upbringing as her brother Felix, sharing a number of his music tutors, including Carl Friedrich Zelter. Like Felix (who was born in 1809), Fanny showed prodigious musical ability as a child and began to write music. Visitors to the Mendelssohn household in the early 1820s, including Ignaz Moscheles and Sir George Smart, were equally impressed by both siblings. She may also have been influenced by the role-models of her great-aunts Fanny von Arnstein and Sarah Levy, both lovers of music, the former the patroness of a well-known salon and the latter a skilled keyboard player in her own right. [Wikipedia]
When Felix Mendelssohn visited England in 1846-7, he had a private audience with Queen Victoria. She told him how much she liked his songs, and asked if she could sing her favorite—Italien from his Op. 8 collection. After she sang it, Felix admitted to her that it was not his, but rather his sister Fanny’s. The Queen had good taste, for Fanny Mendelssohn was a marvelous composer, largely under-appreciated to this day. Extraordinarily gifted, she could have given the world so much more than she did, if she had had the courage. She face overwhelming pressure to conform, and rebellion would not have been tolerated.