Now we begin the symphony proper, with a long movement called Roméo seul that, like many first movements of symphonies in the tradition of Haydn and Mozart and Beethoven, starts with a slow introduction, Andante malinconico e sostenuto. But the theme of the introduction is untraditional: an immensely long line, sparsely accompanied, not so much an intelligible melody as a pitch-contour suitable for shading and expressive shaping—a sort of naked expressivity purged of easily interpreted expressive devices, a stile molle not quite certain exactly what form of melancholy it wants to take (see ex. 5). It is difficult to grasp the form of the whole line, difficult even to grasp the key: sometimes it seems to present itself in F major (appropriate to the single-flat signature), but it seems equally at home in C major and A minor, and has distinct sociopathic tendencies to the remote key of E major. It is a juvenile- delinquent melody, sullen, tentative, rebellious, unpredictable. Although its direction keeps wavering, the listener soon grows accustomed to a half-articulate pattern of a leap, a sustained note, and, trailing off the sustained note, an irregular chromatic droop. It is a tune without a Gestalt, persistently unsuitable to symphonic development. Or, to put it another way, it can't be developed precisely because it keeps developing itself, as segments of itself keep looping back to other keys. Symphonic development is largely a matter of extracting pieces of a theme and subjecting those pieces to sequential treatment; but in a long, auto-sequencing theme, such as Berlioz's introduction to Roméo seul (or the idée fixe of the Symphonie fantastique), it is impossible to distinguish exposition from development.

Why would Berlioz want to begin the symphonic part of his Roméo et Juliette in such a state of musical obscurity? One reason is that it is evidently evening, and the thick dimness of the music, as it gropes for a theme, reflects the time of day.