In 1941, the Spanish cellist Pablo Casals and the famous Polish harpsichordist Wanda Landowska were both living close to each other in the South of France: he to get away from the Fascists in Spain, she to avoid the Nazis invading France.

On today’s date that year, Casals paid Landowska a visit, and she played some Bach for him. Casals asked her why she played the trills starting with the upper note, since he was used to the opposite. Landowska explained her reasons, and—for further evidence—showed Casals the entry on trills Leopold Mozart's “A Treatise on the Fundamental Principles of Violin Playing” which was published in 1756, just six years after Bach’s death. Casals was still not convinced.

So, with a smile, Wanda said: "Let us not fight anymore. Continue to play Bach your way and I, his way." They both laughed and moved on to other subjects.

Denise Restout, Wanda’s pupil and long-time companion was an eyewitness that day, and decades later, after Landowska’s death, confirmed her memory of what actually occurred by asking Casals himself. She did this because Landowska’s teasing comment was being attributed to or redirected at all sorts of other people, including the famous Bach pianists Rosalyn Tureck and Glenn Gould.

Ms. Restout wanted people to know that Landowska was just making a little joke about trills and not disparaging how other musicians played a composer both Casals and Landowska loved above all others.