Beethoven began the Fourth Piano Concerto in 1805 and worked on it throughout 1806. He played it in a private performance at the palace of his patron and friend Prince Lobkowitz in March 1807. But it was not until December 22, 1808, that he played it publicly in a legendary concert that saw the premieres of the Fifth and Sixth Symphonies, the Choral Fantasy, and parts of the Mass in C. At least one audience member found the experience physically and mentally numbing, writing: “There we sat from 6:30 till 10:30 in the most bitter cold, and found by experience that one might easily have too much of a good thing.” Even had there been heating, the concert undoubtedly suffered from inadequate rehearsal, and occasionally from Beethoven’s poor direction. By this time, he was becoming more and more deaf, and the Fourth is the last of his concertos that he was able to perform from the keyboard.

The three movements of the concerto are remarkably different from one another. The first is scored for strings, woodwinds, and horns, without trumpets or timpani. Its unusual opening begins with the solo piano introducing a stately, reflective theme built on the short-short-short-long rhythm that characterizes much of the music from Beethoven’s middle period. The orchestra enters immediately with the same theme, but in the surprising key of B major. Beethoven often used these “wrong-key” entrances and achieved a variety of effects with them. Here, it instantly changes the mood, like stage lights changing color.

In the second movement, brusque passages in octaves from the strings (the winds are silent) are answered by gentle chords from the piano. By movement’s end, the strings are playing soft harmonies under the piano, as if they have been lulled. The piano writing is extraordinarily subtle and delicate. Beethoven’s newest piano at the time he was composing had three strings for each of the upper notes, like the modern instrument. Unlike the modern instrument, its pedal mechanism shifted the hammers so they could hit one, two, or all three strings, providing remarkable control not only in loudness but also in tone color: On one string, his piano could achieve a ghostly chime, not unlike a celesta. Beethoven asks for “una corda” and “due corde” in the second movement. The player of a modern grand piano can only approximate the effect.

The Rondo finale begins quietly, with a little fanfare figure in the strings that begins in C major, before making its way around to G. After it has been heard twice, the trumpets and drums, at long last, make their entrance in a frenetic explosion of sound. —Howard Posner