I first heard Fanny Mendelssohn-Hensel's music when I was studying music history as an undergrad. The CDs that accompanied the Third Edition of the Norton Anthology of Western Music had one of her solo piano pieces on it, and I loved it.
Felix is wonderful; Fanny, four years his senior, is sublime. Her music is, at times, less perfectly constructed than her brother's, but far more harmonically bold.
Her banker father, along with the rest of society, felt is was unbecoming for a woman to be a professional musician. Fanny's close friend, pianist/composer Clara Schumann, was able to perform in public because she was of a lower class.
Fanny married Wilhelm Hensel, a painter and poet, in 1829. She set some of his words to music. They named their only son after Fanny's favorite composers: Sebastian Ludwig Felix Hensel, who went on to write a biography called The Mendelssohn Family.
When Fanny and Felix were younger, Felix would publish her music under his name. In 1846, more than a decade after her father's death, Fanny told Felix she wanted to publish music using her own name.
Her 12-part piano cycle based on the months of the year, Das Jahr, was published in 1847, but Fanny died before she could read the favorable reviews.
"Madame Hensel was an unforgettable musician, an excellent pianist, an intellectually superior woman. She was small, almost slight, but the fire that burned in her eyes revealed extraordinary energy. As a composer, she was exceptionally gifted ..." Charles Gounod