This presentation develops a new theory of symphonic “Breakthrough” (Durchbruch) to recontextualize the role of “deformation” within fin-de-siècle modernism. Originally formulated in Adorno’s Mahler book, Breakthrough is a formal rupture which critically alters a work’s technical and expressive narratives. By undermining straightforward conceptions of a unified, hermetically sealed work, it resists a standardized account. Within Hepokoski’s discussions of Strauss’s Don Juan and Sibelius’s Fifth, Breakthrough is a “deformation” deployed by fin-de-siècle modernists to develop sonata form. Despite widespread adoption of Hepokoski and Darcy’s “Sonata Theory,” Breakthrough’s modernist tendencies remain underappreciated within the New Formenlehre. While subsequent authors like Harper-Scott and Tarrant examine a wider range of Breakthroughs, none substantially revise Hepokoski’s original conception. Breakthrough’s narrow grounding in Mahler, Strauss, and Sibelius is troubled by Romantic Formenlehre developments from Vande Moortele and Schmalfeldt, which normalize understanding of apparently “deformational” practices and necessitate further expansion of music theory’s evidential corpus. Critiquing deformation’s hermeneutic and socio-political baggage, Horton, Straus, and Wingfield further complicate its relationship to modernism and wider nineteenth-century practices, underscoring the challenges of fin-de-siècle form and the need for better theoretical frameworks. Breakthrough therefore engages deformation’s disciplinary relevance for theorizing modernist, fin-de-siècle form.

This presentation’s new theoretical framework demonstrates how Breakthrough’s irruptive effect is a critical technique for deconstructing fin-de-siècle sonata form. Grounded in a corpus study of nineteenth-century symphonic works, this model integrates Hepokoski’s original conception with theoretical discourses surrounding parageneric spaces, sonata typology, form-functional Becoming, and two-dimensional form. This approach demonstrates how Hepokoski’s 1860s generation uniquely deploys Breakthrough to complicate and critique traditional forms. Their diverse Breakthrough practices catalyze different types of multidimensionality (Mahler, Strauss), formal truncation (Glazunov) and compression (Sibelius), progressive, teleological trajectories (Nielsen), and cadential deferral and non-diatonic tonal relations (Elgar). These diverse modernist strategies destabilize structural foundations and challenge hermeneutic boundaries, thereby critiquing different aspects of the preceding symphonic tradition. By contextualizing its fin-de-siècle manifestations within broader nineteenth-century procedures, a multi-faceted account of Breakthrough’s deformational nature clarifies how modernist practices deconstruct sonata form. This presentation’s more robust framework therefore elucidates Breakthrough’s critical impulse and facilitates a deeper reconsideration of deformation and modernism within the New Formenlehre.

Scholarship on nineteenth-century sonata form makes no secret about Romantic-era composers working in dialogue with norms concretized by their predecessors (Richards 2013; Davis 2017; Osborne 2021). Such engagement with tradition encourages investigations regarding “how an evolution of musical ideas may override the tonal norms of sonata form in ways that produce satisfying results” (Brown 2013, 374). Emilie Mayer’s sonata strategies adeptly twist Type-3 norms, yielding idiosyncratic variations on traditional sonata form. Using Mayer’s solo sonatas as case studies, I explore approaches that she utilizes in S-Space that are fundamental to her formal aesthetic; strategies that exploit thematic- and closure-related differences between the exposition’s and recapitulation’s S-Space that generate friction against common complications within this action zone.

A unifying feature in Mayer’s approach to S-Space is her penchant for using what I call Compound S-Modules (CSM), where the S theme initially appears and reaches a cadence, departs to contrasting material, then returns to the same S theme, which now concludes with a different level of closure. Such a return to S is unusual, exploiting a harmonically-closed theme that typically yields to C-Space’s closing impulses (Caplin 1998; Hepokoski & Darcy 2006). For example, in Mayer’s D-minor Piano Sonata, expositional CSM-Space reaches an EEC (IAC: III), yet the recapitulation avoids closure during the CSM and departs to C rhetoric, eventually providing structural closure with a PAC: i only upon the coda’s arrival. Mayer’s C-minor Violin Sonata follows a different CSM trajectory. In the exposition, S reaches what appears to be an EEC with a PAC: v, followed by a C-Space PAC: VI. In the recapitulation, the analogous ESC falls on an unexpected PAC: natural-vii and then passes through what was C-Space to reach the ESC (PAC: i). This reinterprets our perception of expositional C-space, and now forms a CSM with the structural close.

While Mayer’s sonatas pay homage to traditional sonata-form guideposts, her S-Space strategies demonstrate an inclination to manipulate thematic development and closure norms. CSMs not only enable detailed descriptions for modular S-Space designs, but also give a first glance into Mayer’s large forms, which have received no analytical consideration to date.

Several studies in recent years have highlighted the specific characteristics of nineteenth-century sonata form (Schmalfeldt, 2011; Vande Moortele, 2013; Taylor, 2016; Horton, 2017; Davis, 2017; Hunt, 2020, among others). Romantic-era music introduced a heightened sensitivity to temporality, with concepts like "becoming" (Schmalfeldt), "functional transformation" (Horton), "atemporal interpolation" (Davis), "lyric form" (Hyland, 2023) and others refining our understanding of Romantic formal processes that challenge the unidirectional flow of sonata-form movements.

This research focuses on a related phenomenon termed "Retracted Tonal Areas" (RTAs). RTAs are thematic action spaces interpolated into one of the two main theme zones of the exposition, occupying a remote tonality, and eventually reverting to the previous key. Most often, RTAs emerge within the S-zone and "interrupt" the flow of the secondary key (SK). On rare occasions, they may occur within the P-zone.

In this paper, I discuss the RTA type that emerges at the beginning of the S-zone, a process labeled "Deferred SK Expositions" (DSK). In DSK situations, the TR establishes the target SK, yet the following S-theme opens in a foreign tonality. Following the thematic part of the RTA, the SK is reclaimed by a transitory passage. These passages do not modulate to further keys (as in most three-key expositions) and often lack energy gain, for which reason they are labeled "S-RT" (SK-retransition). This model differs from existing concepts such as "Modulating Subordinate Theme," "MC Declined," and "Trimodular Block." DSKs (and RTAs in general) do not progress linearly but rather highlight a circular tonal narrative. They specify a stable and satisfactory theme zone that suspends the expositional progression. Such situations sometimes encompass the entire S-zone and lead directly to the closing section.

Most studies on tonal expansions in early nineteenth-century sonata expositions focus on works by canonic composers, especially Schubert. In contrast, this research surveys sonata movements by a wide range of early Romantic composers whose works have generally been underexplored, such as Dussek, Reicha, Kuhlau, Pixis, Hummel, Spohr, and others. The paper will elaborate on various RTA subtypes and discuss specific DSK examples.