Fanny Mendelssohn, Felix’s older sister, was also a highly prolific composer. The siblings were always very close; music was one of their bonds, for Fanny showed as much talent as her brother. Married to a painter named Wilhelm Hensel, she devoted herself to weekly concerts at the Mendelssohn home in Berlin, for which she composed music of all kinds, including even oratorios.

However, Fanny’s music did not pass beyond the threshold of the Mendelssohn mansion. Only a small percentage of it found its way into print, at the end of her short life. Fanny is often seen as a victim of patriarchal society and of the general refusal in the past to take women composers seriously. Like Mozart’s sister Nannerl, she watched as her younger brother built a great career, while she was expected — indeed, conditioned — to put motherhood and family first, music second. But we should remember that unlike other successful women composers of the nineteenth century — from Louise Farrenc (1804–1875) to Clara Schumann (1819–1896) to Cécile Chaminade (1857–1944) and Ethel Smythe (1858–1944) — Fanny Mendelssohn belonged to the upper class. Few members of this class, male or female, had ever pursued public careers in the arts. They didn’t need the rat race. Workaholic Felix was an exception.

Fanny’s sudden death at age forty-one devastated Felix and hastened his own death only six months later.