From 1831 to 1836, Victor Hugo and Louise Bertin collaborated on an opera titled La Esmeralda. For Hugo, it would be the only opera libretto he would ever write, a mere footnote to his collection of widely admired novels, plays, and poetry; for Bertin, however, it would become her most important work, yet seemingly destined to fade into obscurity like so many great pieces of art. Using Schenkerian analysis, this thesis uncovers the tonal and voice-leading structure of the first act of La Esmeralda. A study of this nature, which operates from the premise that forms as large and complex as opera can be examined in terms of a large-scale structure, is valuable because it sheds new light on the correlation of tonal structure and dramatic organization. Through these methods, Act I of La Esmeralda is read as a background progression from D major (with F# kopfton) to F major, composing-out an F#/F♮ dichotomy introduced in the overture. With reference to several musical-symbolic ideas - including the representation of virtue through the pitch F#, the key of Notre-dame's bells - it is shown how the musical structure of Act I expresses the Hugolian themes of fate and decay.

When talking about tonal music, we sometimes tend to take for granted the idea that the tonic should always be clearly established either at the beginning or the end. However, there are composers who sometimes deviate from the normal path by creating different types of riddles or tonal enigmas in their works. Some of these riddles can be solved later on as the piece progresses; yet others may need to bexplained with the help of some external references. This thesis examines three such examples, each of which poses its unique enigma. The second movement of Bruckner's Symphony No. 1 presents a dualism between Ab and F (paralleled by their dominants Eb and C); Brahms's Alto Rhapsody involves an enormous auxiliary cadence spanning 2/3 of the piece and a seemingly plagal cadence which turns out to be authentic with the V suppressed; and eventually, Grieg's setting of Dereinst, dereinst, Gedanke mein provides a paradoxical ending which may be understood as incorporating the composer's attitude towards the text.