Wanda Landowska (1879–1959) was a Polish-French keyboard player and composer and an important figure in the revival of the harpsichord in the twentieth century. In 1925 she established the École de Musique Ancienne in Saint-Leula-Forêt outside of Paris, and students from the United States and elsewhere came to France to study with her. She left Paris in 1940 to escape the Nazis and shortly thereafter moved to the United States. She found a home in Lakeville, Connecticut, where she continued performing, teaching, and recording.

RK went to France in 1931–32 on a John Knowles Paine Fellowship to study with her. As is well-known, the relationship between the two was somewhat problematic. Before RK began his studies with Landowska, he indicated that he would probably not agree with her musical interpretations, but he hoped to gain insights into technique. He did not like the atmosphere of the school and often disliked Landowska's methods and performances, but he did feel that his technique improved as a result of her teaching, and he also wrote positively about some of her performances. The break between them occurred when he wrote a letter to a friend in Concord, Massachusetts, that included criticisms of her, and the contents of that letter were reported to her. I am not absolutely sure whether the letter below was actually sent to Landowska, but RK indicated in other letters to family members that he was going to write a letter of apology to her because, in spite of his very mixed feelings about her, he thought it was possible that he might gain something from further study with her. However, he did not study with her again.

July 30, 1932

My Dear Madame Landowska,

I hope you will forgive the delay of this letter, caused by the distractions of “déménagement” and travel.

This is to tell you how much I regret the creation of the unfortunate report that has come back to you.