She grew up in Berlin and received a thorough musical education from teachers including her mother, as well as the composers Ludwig Berger and Carl Friedrich Zelter.
Owing to her family's reservations and to social conventions of the time about the roles of women, six of her songs were published under her brother's name in his Opus 8 and 9 collections.
[9] Beyond inspiration from her mother, Mendelssohn may also have been influenced by the role-models represented by 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.
[10] After studying briefly with the pianist Marie Bigot in Paris, Mendelssohn and her brother Felix received piano lessons from Ludwig Berger and composition instruction from Carl Friedrich Zelter.
At one point, Zelter favoured Fanny over Felix: he wrote to Johann Wolfgang von 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.
[13] Much later, in an 1831 letter to Goethe, Zelter described Fanny's skill as a pianist with the highest praise for a woman at the time: "... she plays like a man.
"[14] Visitors to the Mendelssohn household in the early 1820s, including Ignaz Moscheles and Sir George Smart, were equally impressed by both siblings.
[15][16] The music historian Richard Taruskin suggested that "the life of Fanny Mendelssohn Hensel is compelling proof that women's failure to "compete" with men on the compositional playing-field has been the result of social prejudice and patriarchical mores (which in the nineteenth century granted only men the right to make the decisions in bourgeois households).
[18] Although Felix was privately broadly supportive of her as a composer and a performer, he was cautious (professedly for family reasons) of her publishing her works under her own name.
[19]The music historian Angela Mace Christian has written that Fanny Mendelssohn "struggled her entire life with the conflicting impulses of authorship versus the social expectations for her high-class status ...; her hesitation was variously a result of her dutiful attitude towards her father, her intense relationship with her brother, and her awareness of contemporary social thought on women in the public sphere.
[31] Their correspondence of 1840/41 reveals that they were both outlining scenarios for an opera on the subject of the Nibelungenlied (which never materialized): Fanny wrote "The hunt with Siegfried's death provides a splendid finale to the second act.
[24] In 1830 came her first public notice as a composer, when John Thomson, who had met her in Berlin the previous year, wrote in the London journal The Harmonicon in praise of a number of her songs that had been shown to him by Felix.
[37] Fanny's support of Felix's music was clearly demonstrated during the 1838 rehearsals in Berlin for her brother's oratorio St. Paul at the Singverein, which she attended at the invitation of its conductor, Carl Friedrich Rungenhagen.
In a letter to her brother she described attending the rehearsals and "suffering and champing at the bit ... as I heard the whining and [the accompanist's] dirty fingers on the piano ...
The consequence was that Rungenhagen consulted her closely about all details of the rehearsals and performance; this included her firm instructions not to add a tuba to the organ part.
"[38] Wilhelm Hensel, like Felix, was supportive of Fanny's composing, but unlike many others of her circle was also in favour of her seeking publication of her works.
[45] On 14 May 1847 Fanny Mendelssohn Hensel died in Berlin of complications from a stroke suffered while rehearsing one of her brother's cantatas, The First Walpurgis Night.
She was also undoubtedly hampered by the fact that, unlike her brother, she had never studied or played any string instruments, experience which would have assisted her in writing chamber or orchestral works.
[53] After completing her string quartet, she wrote to Felix in 1835, "I lack the ability to sustain ideas properly and give them the needed consistency.
Two other works for orchestra, soloists and choir were written in that year, Hiob (Job) and an oratorio in sixteen sections, Höret zu, merket auf (Listen and take note).
[64] The musicologist Stephen Rodgers has claimed that the relative lack of analysis of Fanny Hensel's music has left the presence of triple hypermeter in her songs mostly overlooked.
He points to this type of meter being used by Mendelssohn to alter the speed of vocals in the song and to reflect emotions through distortion of duple norms.
[65] He also points to a lack of tonic harmony as a recurring characteristic of her lieder, identifying it in the lied Verlust (Loss) as a deliberate means to reflect the song's themes of abandonment and failing to find love.
[66] She commonly used strophic form for her songs, and her piano accompaniments frequently doubled the voice-line, characteristics also of the music of her teachers Zelter and Berger.
[67] Though the foundation created by her teachers would remain, Rodgers suggests that she increasingly turned to through-composed forms as her style developed, as a way to respond to elements of poetic text.
Selected letters and journal entries were published during the 19th century, notably by Sebastian Hensel in his book on the Mendelssohn family.
[22][76][77] During the 19th century Fanny mainly figured as a bystander in biographies and studies of her brother Felix; typically she was a representative of a supposed 'feminizing' influence that sapped his artistry.
[78] In the 20th century the conventional narrative switched to presenting Felix as disapproving of his sister's musical activities and seeking to contain them, whilst the 'feminizing' accusation against Fanny evaporated.
... Hensel fits neatly into a traditional narrative of the suffering artistic genius ... with a modern twist: the feminine gender of its main character.