Elder sister to composer Felix Mendelssohn, Fanny was arguably the more talented sibling, but was held back throughout her life by Felix himself, as well as their father. Their suffocating dynamic empowered Felix to prevent her from pursuing a career as a composer. Although she wrote almost 500 beautiful compositions, he and their father forbade her from publishing them or performing in public. Even as he supported Felix’s career, their father told Fanny, "Music is likely to become a profession for Felix, while it is only an ornament for you; it may never form the core of your life." Even her marriage could not free her from her father and brother’s control. Even after her father’s death in 1835, Felix continued to actively prevent her from pursuing success.
During his lifetime, Felix himself acknowledged stealing Fanny’s works and claiming them as his own — even admitting to Queen Victoria that her favourite of his pieces (Italien) was actually written by Fanny. Several of Fanny’s compositions were published under Felix's name in his Opus 8 and 9 collections. She also likely developed the Lied ohne Worte (Song without Words) genre typically attributed to Felix. Additionally, he sought her opinions on all of his own works and her insights helped shape their final versions. Fanny unfortunately died shortly after freeing herself from his control, the year after she published her own first opus. If not for the stroke that killed her, she may have truly come into her own as a composer and received the recognition she deserved.
After her untimely death at age 41 in 1847, her personal documents were left to her family, who did nothing more to support her career than they had during her life — in other words, nothing. In 1965, most of her works became part of the West Berlin State Library’s Mendelssohn Archive, under the control of Dr. Rudolf Elvers, who likewise largely kept her works from the public for decades. As reported in 1986:
But he says the rest of her work must first be carefully transcribed and checked against all available source material, and that qualified musicologists are not interested. "I am waiting for the right man for the job to come along,'' he adds, after first complaining about "all these piano-playing girls who are just in love with Fanny.'' Contrasting her life with Felix's, he says, "She was nothing. She was just a wife'' with the name Mendelssohn.
He maintains that serious musicologists and publishers have little interest in her work because "it's too much, and it's not so good.''
Elvers also told a small gathering of scholars at Brandeis recently, "I don't believe she will play an eminent role in music history.'’
Because her works were not published during her life, they generally do not meet the criteria for public domain, and groups that wanted to perform her pieces were typically denied by Elvers, as were scholars wanting access for research purposes. This was not the proverbial benign neglect of so many individuals and institutions towards women’s work — this was a misogynist deliberately undermining and gatekeeping the work of someone whose legacy he was entrusted with. When he said "I don't believe she will play an eminent role in music history," this was a prophecy he did his best to see fulfilled — we are only fortunate that her legacy outlived him and more recent decades have seen her work performed in concerts and recordings, as well as academics publishing books and articles about her life and work.
Read more about her on the Infinite Women site: https://www.infinite-women.com/women/fanny-hensel/