B minor
In Baroque times, people thought that B minor was the key of passive suffering. Christian Friedrich Daniel Schubart (1739-1791) said that it was a key that was complaining gently and quietly, something that matches Bach's use of the key in the St. John's Passion. By Beethoven's time, B minor had changed in people's minds: Francesco Galeazzi wrote that B minor was not suitable for music in good taste, and Beethoven labelled a B minor melodic idea in one of his sketchbooks as a "black key".