Fanny Mendelssohn composed over 450 pieces of music. Her compositions include a string quartet, a piano trio, a piano quartet, an orchestral overture, four cantatas, over 125 pieces for the piano, and in excess of 250 lieder (art songs). Six of her songs were originally published under Felix's name in his Opus 8 and 9 collections. Her piano works are often in the manner of songs, and many carry the name Lied für Klavier (Song for Piano), analogous to Felix's Lieder ohne Worte (Songs Without Words). This style of piano music was most successfully developed by Felix, whose first set (Op. 19b) appeared in 1829–30, with a second set (Op. 30) appearing in 1833–34. Fanny's sets of Lieder für Klavier were written in the period 1836–1837, at about the same time as Felix's set Op. 38.

The majority of Fanny Mendelssohn's compositions are limited to lieder and piano pieces as she felt her abilities did not extend to larger, more intricate compositions. 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. 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. Therefore lieder suit me best, in which, if need be, merely a pretty idea without much potential for development can suffice." She was an early example of women composers of a string quartet; she had also earlier written, with the assistance of Zelter, a piano quartet in 1822 (her first large-scale work), and, despite her reservations in her letter to Felix, she wrote in her last year a piano trio (Op. 11). Her Easter Sonata written in 1828, was unpublished in her lifetime. It was discovered and attributed to her brother in 1970, before examination of the manuscript and a mention of the work in her diary finally established in 2010 that the work was hers.

April from the manuscript of Fanny Hensel's Das Jahr(illustration by Wilhelm Hensel)

Most of Hensel's work after her marriage was on a small scale, songs and piano pieces. In 1831 for the first birthday of her son Sebastian, she created a cantata, the Lobgesang (Song of Praise). 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). In 1841 she composed a cycle of piano pieces depicting the months of the year, Das Jahr (The Year). The music was written on tinted sheets of paper and illustrated by her husband, with each piece accompanied by a short poem. The writer Kristine Forney has suggested that the poems, artwork and coloured paper may represent the different stages of life, with others suggesting they represent her own life. In a letter from Rome, Fanny described the process behind composing Das Jahr:

I have been composing a good deal lately, and have called my piano pieces after the names of my favourite haunts, partly because they really came into my mind at these spots, partly because our pleasant excursions were in my mind while I was writing them. They will form a delightful souvenir, a kind of second diary. But do not imagine that I give these names when playing them in society, they are for home use entirely.

After Das Jahr her only large-scale work was her Piano Trio Op. 11 of 1847.

Source: https://en.wikipedia.org/wiki/Fanny_Mendelssohn / License: CC BY-SA 4.0