This place of wonder leads us, at last, into the allegro – the exposition. (MUSIC) For me, one of the important points about this allegro is that even though it is fast and energetic, it is still part of the movement called "farewell". Even when it is joyous, it’s an uncertain, ambivalent joy. You’ll notice that when the exposition proper begins, we haven’t landed anywhere firm. (MUSIC) Contrast that with Pathetique, the only preceding sonata with a substantial introduction. (MUSIC) The allegro arrives and brings with it a terrible certainty. The beginning of this allegro, on the other hand is a transitional passage which – by means of several more groups of three notes -- has to search its way back to E flat major. (MUSIC) But even this E flat major – the first "theme", not that it’s really a theme – is not so emotionally stable. It’s less a theme than an upward surge – I hear it as ""determined yearning"– that lasts, you guessed it, three notes... (MUSIC) ..Just as is the second theme also does. (MUSIC) It really is remarkable, just how many of the ideas in this movement are three note ideas, which ties them instantly, no matter what other qualities they have, to the notion of "farewell". This second theme, in fact, not only features the three note unifying device, but the movement’s OTHER unifying device as well: the chromatic series of notes that initially all got played with the same finger. (MUSIC) This chromaticism, this juxtaposition of flat and natural, keeps the music a bit shifty and nervy –it reminds us that this movement is The Departure, even at moments when the sheer speed of events might make it seem happy-go-lucky. The exposition’s closing theme is again three notes long, and not only that: this is a direct reference to the opening "Le-be-wohl" theme. (MUSIC) All three of these themes – first, second and closing – occur within a minute of one another. The extreme compactness of the exposition, combined with the way that all the themes, in one form or another, refer back to the opening, that drives home how the movement is dominated by the "Farewell" idea, and by extension, how it's dominated by the introduction. Really, it is so much more than an introduction, in a totally different way from how the Pathetique’s and Tempest’s introductions were. In length, and in its motivic importance, it dominates the whole movement. The development is, surprise surprise, also dominated by a version of the opening theme. (MUSIC) At the beginning of the piece, the le-be-wohl motive was pointed downward, and the dominant impression it gave was of gravity. Now, in the development, when the second downward step becomes an upward leap, usually with a dissonant chord attached to it (MUSIC), the impression changes to one of discomfort. That's already brilliant development – taking the movement’s materials, and transforming them just with a minor tweak – but it’s made even more brilliant by the way Beethoven combines the motive with the opening of the allegro, also tweaked. (MUSIC) Honestly, this is so ingenious, and again shows how totally integrated the introduction is into the rest of the movement.