“I am writing to you with an erection on my head and I am very much afraid of burning my hair”, wrote Nannerl Mozart to her brother Wolfgang Amadeus. What was being erected was a large hairdo on top of Nannerl’s head, as she prepared to pose for the Mozart family portrait. It was that hairdo that drew my attention. Nine years ago I was visiting Vienna for the 250th birthday celebrations of Wolfgang Amadeus, and I was thrilled to explore the city following in Wolfi’s footsteps, many of which turned out to be Nannerl’s as well. At the Mozarthaus Vienna – Wolfgang’s apartment – on the exit wall, as if by an afterthought, there was a little copy of the Mozart family portrait. I saw a woman seated at the harpsichord next to Wolfgang, their hands intertwined, playing together. I grew up studying to become a violinist. Neither my music history nor my repertoire included any female composers. With my braided hair I was called “little Mozart” by my violin teacher, but he meant Wolfi. I never heard that Amadeus had a sister. I never heard of Nannerl Mozart until I saw that family portrait. I was intrigued and determined to find out more. I read Wolfgang Mozart biographies, studied the situation of women and female artists during Mozarts’ time and in different countries, read writings of Enlightenment philosophers, conduct manuals … But the richest source of information came from the Mozart family letters. There are hundreds, and we have them because Nannerl preserved them. Most are written by Leopold and Wolfgang but some of Nannerl’s letters survived as well. Through these letters, sometimes only from the replies to her lost letters, Nannerl slowly emerged. I was able to understand the Mozarts as people, as a family, and through the lens of the times and the social situation in which they lived. I saw Nannerl’s potential, her dreams, her strength, grace and her fight.