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Characteristics of the Sonata Principle

M.Tevfik Dorak

* Sonata principle is the most important principal form of formal design in the Classical period. It is based on a movement away from and back to the principal key. The key scheme is clearly articulated, associated with, and dramatized by contrast of material. Sonata form is used to create a drama by setting up a conflict between two keys in the exposition, working out this conflict in the development, and reaching a resolution at the recapitulation

* In the Classical period, it is the tonal structure that creates the drama of the movement which became the thematic contrast in Romantic music

* A movement written in sonata form falls into three sections: exposition (statement), development (fantasia), and recapitulation (restatement). Almost in all early sonata form movements the exposition is repeated giving rise to a scheme AA:BA'. It integrates three parts in a two-part structure (three-part design and two-part tonal structure).

All possible sections in a movement written with the sonata principle are: Introduction, first subject (group), bridge passage, second subject (group), closing theme/group (not codetta) / development / recapitulation (first subject, bridge passage, second subject, closing theme or group) / coda.

* The exposition divides into a first group in the tonic and a second group in another key, most often the dominant (or the relative major), and less often in the dominant minor.

* The contrast of mood between the lyric quality of the second subject and the dramatic quality of the first. The themes are expected to be capable of development. Towards the end of the second group, there may be a closing group (not codetta) with an individual character. Romantic composers often gave thematic material free scope without regard to formal considerations.

* From Haydn's monothematic treatment of the sonata principle [based on purely key relationships], the additional thematic contrast [between the subjects] of the late classical sonata principle evolved. In the early Romantic period [Schubert], thematic importance elevated above the tonal importance. Thematic contrast became more important than the key relationships.

* The first group ends with a half-cadence on (but not in) the dominant, followed immediately by the second group actually in the dominant. More often, especially after 1780, a transition (bridge passage) appears. The transition often develops out of a restatement of the main theme.

* Between the first and second subjects, there is a clear modulation to, and cadence in, the dominant key. (The first subject is expected to be developed in the bridge passage.) The passage to the dominant usually implies the dominant of the dominant. This is because the dominant key must be arrived and established despite the pull of the tonic. This is generally achieved via the dominant of the dominant to establish the dominant itself more strongly. The bridge passage is full of tonal activity and a busy part of the score and ends with a decisive cadence. The important structural points, such as the beginning of the bridge passage and second subject, are marked by thematic contents as well as features like rests.

Exposition in a major-key piece:

(Introduction) and first subject in the tonic - half-cadence in the dominant - bridge passage [using the main theme] modulating to the dominant via its dominant - cadence in the dominant (and a rest) - second subject in the dominant - closing group - cadence in the dominant.

* Second half is always longer

* The important means of development technique are melodic segmentation, rapid harmonic modulation (often based on sequences), contrapuntal imitation of melodic motives (fugal style), combination of a theme with a counterpoint, contrapuntal combination of different motives, juxtaposition of contrasting themes originally stated separately, increased complexity of texture, alteration of the rhythmic structure, use of themes and motives in inversion or diminution and so forth. The development section modulates widely, develops the material and increases the complexity of the texture. The development may use only one theme from the exposition or several.

* The emphatic re-appearance of the tonic after modulatory development section is prepared by dominant preparation

* The recapitulation is announced by a simultaneous double return: to the main theme and to the tonic. Neither a simple restatement of the main theme, nor a simple return to the tonic, has the immense impact of this double return.

* The recapitulation almost always enters unambiguously with the double return of the opening theme in the tonic. When two or more themes occur in the first group, the return to the tonic may co-incide with the second of these; the opening theme then appears in a foreign key, immediately afterwards in the tonic; or as a coda following the second group (in the sonata form, the main theme has to return).

* In the recapitulation, the second subject can start in any key but it has to go to the tonic. It can appear in the tonic major in a minor-key piece. The bridge passage in recapitulation is modified and as there is no need to modulate to the dominant, it is usually shortened

* Almost every coda restates the main theme. As befits the end of a large tonal structure, most codas include some emphasis on the subdominant, especially if none has occurred in the recapitulation.

* In the nineteenth century, it became legitimized that the sonata principle was based on the duality of two contrasting themes rather than on the tonal duality of the exposition. Another aspect of the 19th century tendency was to displace towards the end of the weight of every form, single movements and whole cycles alike. Thus, the coda increased in importance.

* The other principal difference in 19th century sonata form is greatly expanded system of tonal relations: the acceptance of major and minor as equally valid representation of the tonic; the use of remote keys in the second group.

* One of the chief distinctions between Classicism and Romanticism is keeping the weight of the form centered on the beginning of the recapitulation (Classicists) as opposed to on the coda (Romantics).

* The first symphony used the sonata principle was written by the Viennese GM Monn in 1740.


An essay on the use of the sonata form in the Eroica and Unfinished symphonies:

The binary form, with central double bars and modulation to the dominant, was the most frequently used musical form until the Classical era. The modulation in the latter half of the first section that creates harmonic tension was essential to the evolution of large forms, such as sonata form. A movement in sonata form consists of the sections called exposition, development, and recapitulation (and the optional ones, introduction and coda). The tonal principle operating within this framework, the sonata principle, is to establish a conflict of two keys, tonic and most frequently dominant; this conflict is resolved in the second half when the music returns to the tonic key and stays there till the end [A314, Unit 18, p.105]. The basic principle is the statement and resolution of a tonal opposition, projected by means of thematic material associated with each tonal area. Although the modulation to the dominant has a historical value, there is no reason why there should be any restriction on the keys used to establish the contrast with the tonic [p.35 in Ref.1]. Rosen lists the mediant and submediant as substitutes for the dominant along with the relative major [p.33 in Ref.2].

The first movements of Beethoven's Third Symphony (the Eroica in Eb, Op. 55, 1803-4) and Schubert's Eighth Symphony (the Unfinished in B minor, D.759, 1822) show some differences of approach that are possible within the sonata principle. They use similar orchestral forces. The first one is in a major key, the second in the minor which is an important factor in the choice of keys to set up the conflict with the tonic. The two movements differ in length. In Beethoven's movement which is almost twice as long in bar numbers, the sections have unequal lengths [A314, Unit 30-31, A314, Fig. 1]. The repeated exposition (302 bars), development (246 bars), and ‘recapitulation and coda’ (294 bars), which can be regarded as a single structural unit in classical sonata form, make up a three-part structure. As the literal repetition of the exposition would not double the structural weight, the overall weight of the movement is towards the end. The huge coda (141 bars) climaxing the movement makes Beethoven's intention as such clear. Schubert's Unfinished has a comparatively shorter development section and a coda of only 41 bars. What these figures suggest is that the Eroica predicts the changing proportions of the symphony in the later Romantic era more than the Unfinished does.

Unlike all symphonic movements previously written by major Classical composers, the development of the first movement of the Eroica is longer than its exposition. The ratio of the lengths of development to exposition in the Eroica is 246/151, and in the Unfinished 108/109. The abundance of short motifs suitable for development in the exposition of the Eroica results in a massive development, whereas, the development in the Unfinished is the same length as the exposition (still longer than an average development in proportion to the exposition [A314, Unit 30-31, Fig. 1]).

The Eroica starts with two tonic chords stating the home key unambiguously. The principal theme is introduced by the cello and uses the individual notes of the tonic chord in four bars. The rhythmic and chordal nature of this theme is in line with the Classical convention and also makes this fragmentary first subject very suitable for development. While the aim of the first subject is to establish the home key, Beethoven introduces a chromatic note as early as in b.7 as a departure from the classical sonata principle. The principal theme is repeated at b.15 with a different ending this time in the tonic and its extension starts the bridge passage in b.23. The bridge passage consists of the extension of the principal theme (b.37) and a new theme (b.45) which seems to have derived from the tail of the main theme. This new thematic material will also be used in the development (b.166 and 220). At the end of the first transition theme, the dominant of the dominant is reached (b.451) through an augmented sixth on the flattened mediant (b.44). During the second transition theme, the horns (b.45-53) and trumpets (b.55/56) play the dominant of the dominant (F) as preparation for the dominant. There are different opinions on where the second subject begins. By the golden rule of exposition that it is the change of tonality which determines the beginning of the second subject group, it has to be the end of the V7-I cadence in Bb spread out in b.53-57. The two main themes of the second subject group (b.57 and 83) both follow a strong cadential progression into the dominant; are lyrical, short (four bars), introduced by the woodwinds, and have a vertical character (more harmony than melody). They contrast with the more horizontal and rhythmic first subject. Their rhythmic structures also vary; the first subject has a square rhythm, the second subject group has more offbeat accents and syncopations.

The tonal scheme of sonata-principle pieces is clearly articulated, even dramatized, by a contrast in musical material, a pause, or some other means [A214, Unit 22, p.15]. Some kind of cadential patterning underlines the key reached at each point [A314, Unit 30/31, p.32]. It is interesting that Beethoven blurs the structural divisions by avoiding such 'full stops'. Schubert, on the other hand, articulates the sections of the exposition in the Unfinished. The movement starts directly with the first subject group (b.1-21) of which the first theme is presented by unaccompanied cello and double bass. The third theme (b.13-21) is repeated and extended in the tonic. Unlike that of the Eroica, the first subject group ends with a perfect cadence in the tonic and an orchestral rest while the bassoons and horns play the four-bars-long transition (IV-V7-I progression in G). A change in the dynamics and the orchestral texture also mark the structural division. The second subject, which appeared without extensive preparatory modulation unlike the Eroica, is not in the expected key (the relative major [D] or the dominant minor [F# minor]), but in the submediant (G). Schubert chooses a 'substitute dominant' to set up the tonal conflict in the exposition. This can be seen as bending the classic conventions of the sonata principle rather than breaking them as he establishes a second tonal area to conflict with the tonic. The second subject moves to G minor in b.63-83, and then returns to the new tonal area G major in b.84/5. The second subject is an eight-bars-long 'tune' with a distinctive syncopated accompaniment and has a different character from the first subject. Its development starts in the exposition (b.73 till the end of the closing group at b.104), and is not developed further after the double bar. In summary, the main sections of the exposition are aurally recognizable in the Unfinished in contrast to the Eroica.

In analogy to its ancestor (open) binary form, the first half of a sonata-form movement should end in the dominant (substitute). In the Eroica, after two closing group themes (b.109 and 135), the (II-V) cadence in b.143/4 closes the exposition in the dominant. The accented discords on the weak beats of b.124-131 are noteworthy. The closing cadence for the exposition of the Unfinished is in the second tonal area (V-I in G, b.103/4). After the cadence, the tonic note is sustained on woodwinds and horns while pizzicato string octaves descending by step take the music back to B minor for the repeat of the exposition. The second ending (b.110b) is modified to change the tonic chord to the dominant seventh of E minor. Both composers ask for the repeat of the exposition and it is crucial to observe this for the balance of the movement in the Eroica as otherwise the home key will have been heard only in the first 22 bars. Neither of them requires the repeat of the second half of the movement.

The development of the Eroica passes through a wide range of keys making extensive use of the rich thematic material of the exposition, mainly the principal theme (in C minor, b.178; in C# minor, b.182; in D minor, b.186; in G minor, b.198; in C, b.300; in Bb, b.338), the second transition theme (in G, b.166; in Ab, b.220). Even a new theme is presented in E minor (b.284) and repeated in Eb minor (b.322). The new theme in E minor follows a very harsh and dissonant section (b.248-279) resolving onto a B major dominant seventh chord (b.283). A strongly rhythmic pattern used within the second subject group also appears in the development (b.186 and 198; cf. b.65) with the opening theme in the bass. There is also a fugal section (b.235-243). The tonic is not visited in the development. This feature of the development together with visits to a diverse set of remote keys strengthen the impact of the return to the home key as well as creating a greater emotional contrast. The tonic is strongly implied towards the recapitulation, first by the use of the tonic minor (b.322), then the dominant (b.338), and finally by the dominant pedal (b.378+). It is reached by a V7-I cadence in b.397/8. Thus, the development of the Eroica draws its material from the majority of the available material as well as a new theme and passes through a large number of keys, has a dissonant section, and still manages to create the sense of returning to the tonic at the end.

In the Unfinished, the development is based almost exclusively on the first theme of the first subject group. Because of its chordal nature, it is more suitable for fragmentation. The more tuneful second subject is not used in the development except its syncopated accompaniment figure (b.150-169). The second and third themes of the first subject group do not appear in the development at all. The range of the keys visited is a significant difference from the Eroica. Schubert starts the development in the subdominant (E minor, b.110), returns to the tonic (b.134), then passes through the only remote keys C# minor (b.146) and D minor (b.154) before returning to the subdominant in b.166. The keys visited in the rest of the development are the tonic, subdominant, dominant and relative major. The development ends with dominant preparation (b.209-217) and a cadence in the tonic (b.217/8). As in the previous section endings, the development ends with rests (b.217/8). Unlike the Eroica, the tonic and its close relatives are predominantly featured in the development. This is against the idea that in the development, a composer would take the opportunity to get away from the tonic and dominant (or substitute) keys that prevail in the exposition to make the double return a big event [p.37 in Ref.1]. Schubert is less concerned with such tonal considerations.

The themes in the Unfinished are more like tunes than motifs. This is melodically attractive but less useful for developmental purposes. The more tuneful a theme is, the less it is suited to symphonic development [A314, Units 21-22, p.80]. For the self-contained tunes, there is not too much to do to develop them except repeating them in sequences (as in b.146, 176, 184). Transposed repetitions of thematic sections in the development rather than true developments is a general Schubertian process in symphonic composition [p.437 in Ref.3; p.504 in Ref.4].

The double return is well prepared in both movements. In the Eroica, the principal theme reappears in the tonic (b.398). Although it moves to F (b.408, on the horn), and Db (b.416, on the flute), these are decorative shifts and the tonality settles in the home key shortly (b.424). The first subject group and the bridge passage are recomposed to allow for these key changes, for variety, and as there is no need to modulate to the dominant. The second group is recapitulated in the tonic (b.460 and 486) literally to maintain the symmetry which would have been destroyed with the huge development and coda. The recapitulation ends with a perfect cadence in the tonic (b.546/7).

In general, when two or more themes occur in the first group, the return to the tonic may coincide with the second of these [p.502 in Ref.4]. Unlike the Eroica, the recapitulation of the Unfinished does not start with the principal theme (b.218). After an extensive working-out of the first theme, Schubert chooses to start the recapitulation with the second of the three themes of the first subject group. The recapitulation is almost a literal repetition of the exposition except the modulations to the subdominant (E minor, in the repeat of the third theme, b.231), the relative major (D major, b.241) and the dominant (F# minor, b.243). The recapitulation of the first subject group unexpectedly ends in the dominant with a perfect cadence (b.251/2). The four-bars-long transition modulates the music to the relative major (instead of the tonic) for the second subject (b.252-256). Although the second subject group is not recapitulated in the tonic, its end is modified by the addition of four extra bars to go back to the tonic (b.276-279). The second subject group ends in b.303 and the closing group starts in B major (cadence in b.310/1). The closing group switches back to the minor mode (b.322) and concludes the recapitulation with a perfect cadence in B minor (b.327/8).

What Schubert does in the recapitulation of the Unfinished is a violation of the tonal aspect of the sonata principle. He does not observe the convention that the dissonance created by the second subject in the exposition by being in a foreign key has to be resolved in the tonic in the recapitulation. The second subject in G major is recapitulated in D major. For his lyrical second subject, he preserves the mode not to change its character. The avoidance of recapitulating the second subject in the tonic is a revolutionary approach to the then well-established sonata principle in symphonic writing.

Both movements end with a coda varying in size. The coda of the Eroica is almost as long as the exposition. The length is intentional to counterbalance the tonal instability of the development by restoring the tonic further in the coda. It begins with a sequence using the main theme in new keys (Eb in b.551; Db in b.557; C in b.561), and spreads out into a new development section. The main theme is presented again by the second violins (b.565) while the first violins play a new decorative accompanying theme. It even recapitulates the new theme of the development which was originally in E minor (flattened supertonic, b.284), first in F minor (the supertonic) (b.581), and then in the tonic minor (b.589). A climax is reached on the main theme with the tonic-dominant swings (b.647-673) followed by the first theme of the second subject group. The long coda full of events centers the weight of the movement towards the end. This is a different approach to the sonata form by Beethoven since the Classical sonata form requires only a final paragraph or two as coda [p.504 in Ref.4]. This kind of treatment of the form later became a feature of the Romantic sonata form.

The coda of the Unfinished is a relatively short one (41 bars). The main function of the coda is to recapitulate the main theme of the first subject group, which has not been recapitulated earlier (b.328). To comply with the structure of the sonata form, the main theme has to return somewhere after the development in the tonic [p.502 in Ref.4]. The coda is in B minor and finishes the movement in that key.

The first movement of the Eroica follows the Classical conventions of the sonata principle for a major-key symphonic movement with its themes in the tonic and then the dominant, followed by a development section ranging through other keys, and then a recapitulation in which all of the exposition themes recur, all in or near the tonic key, and a substantial coda concludes the movement. Conflict and resolution of both subjects and tonalities are achieved. The Eroica also represents a typical example of Beethoven's personal characteristics in his approach to the sonata form: the use of motifs rather than themes as principal structural material (consequently extensive developments), the presence of groups in place of single themes, interest in sudden key changes and far-reaching modulations [p.408 and 420 in Ref.3]. With blurred demarcation of sections, extensive development, new heights of thematic fragmentation, introduction of a new theme, and accented harmonic clashes, the first movement is a significant expansion of the traditional sonata form.

On the other hand, the first movement of the Unfinished, despite being in sonata form with its themes (first and second subjects) and structure (well-articulated exposition, development, recapitulation and coda), does not observe the tonal plan of the sonata principle. The second subject is not recapitulated in the tonic but in the relative major. The tonal conflict is created by moving away from the tonic but not resolved by returning to it. The 'drama' of the movement is then provided by the contrasting themes. The more tuneful nature of the second subject is one of the first signs of what was going to come in the Romantic period. Both symphonies herald different aspects of the Romantic sonata form. Therefore, the differences cannot be attributed to a higher tendency of either composer to Romanticism.

The major difference between them, that is the unusual tonal plan of the Unfinished, reflects the decreasing importance of the conventional tonal plan of the sonata principle in Romantic music. In Romantic music, key relationships are less important than thematic relationships. The contrast between the themes and their lyrical nature are more relevant. This shift of emphasis is emerging in the Unfinished. It is no surprise that the keys Schubert chose for his second subject in the Unfinished are the submediant and the mediant. The third relationships as the device of moving from the tonic, often seen in Beethoven, were a potent means for Schubert to enrich his harmonic scheme [p. 434 in Ref.3]. He used the submediant key to set up the tonal conflict in the exposition also in his Tragic Symphony in a minor key [p.74 of Ref.5]. He does what he likes but not what the Classical conventions impose. In retrospect, these modifications can be called forward-looking as later in the nineteenth century, such tonal deviations became a norm in Romantic music.


1. Cole W. The Form of Music. London: The Associated Board of the Royal Schools of Music, 1986.

2. Rosen C. The Classical Style. London: Faber & Faber, 1976.

3. Ulrich H. & Pisk P.A. A History of Music and Musical Style. New York: Harcourt Brace Jovanovich, Inc., 1963.

4. Webster J. Sonata form. In: Stanley Sadie (ed). The New Grove Dictionary of Music and Musicians. London: Macmillan, Vol.17, 1980.

5. Chusid M. Symphony in B minor ("Unfinished"). New York: WW Norton & Co., 1971.

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M.Tevfik Dorak

Last updated on Oct 4, 2004