Saint-Saëns wrote in every 19th-century musical genre, but his most successful works are those based on traditional Viennese models, namely sonatas, chamber music, symphonies and concertos. Well schooled in the works of Bach and Beethoven, he was influenced at an early age by Mendelssohn and Schumann. His essentially Viennese upbringing was coloured by the French musical tradition of his day, and salon pieces, operas, and Spanish and exotic compositions survive in abundance. Moreover, his keen historical sense led him to revive many 17th-century French dance forms (bourrées, gavottes, menuets etc.), and his feelings of national loyalty are reflected in numerous marches and patriotic choruses. Towards the end of his life, he developed an austere style comparable to Fauré's. Throughout his career his art was one of amalgamation and adaptation rather than that of pursuing new and original paths; and this led Debussy to epitomize him as ‘the musician of tradition’. Saint-Saëns himself suggested: ‘I am an eclectic spirit. It may be a great defect, but I cannot change it: one cannot make over one's personality’.
Saint-Saëns's musical language is generally conservative. Although some of his melodies are supple and pliable, many are formal and rigid. They are usually built in well-defined phrases of three or four bars, and the phrase pattern AABB is characteristic. The most distinctive aspect of his music is his harmony, in which he was influenced by the theories of Gottfried Weber. Modulations by 3rds are typical, and while most chordal progressions are simple and direct, the many digressions and alterations lend nobility or charm to the music. He had a tendency to repeat rhythmic patterns, not only in his dance music, but as a general aspect of style or to create an exotic atmosphere. He preferred ordinary duple, triple or compound metres (3/4 is often designated as 3) and the use of unusual or free metres is rare (though a 5/4 passage occurs in the Piano Trio op.92 and one in 7/4 in the Polonaise for two pianos op.77). Cross-accents are frequent (the Second Symphony op.55 and the Second Violin Sonata op.102), as are changes of metre within a movement or phrase (First Violin Sonata op.75). Although he was a competent orchestrator, he achieved his sense of colour more by harmonic means than by purely orchestral effects. Throughout his career he was a master of counterpoint, which he learnt from Cherubini's manual in use at the Conservatoire. His mastery of this aspect of his art is evident in the fugues in his three sets of keyboard pieces (opp.99, 109, 161), but his contrapuntal craft is a general characteristic of his style and pervades most of his works. He adhered to traditional forms in his neo-classical and sonata-orientated compositions, but allowed himself more formal freedom in descriptive pieces.
Most of Saint-Saëns’s juvenile works remain unpublished, as do a great number of unfinished cantatas, choruses, songs and symphonies written before 1850. The most ambitious work of these early years was the Symphony in A (c1850). With the appearance of the Symphony no.1 (1853) and the Piano Quintet op.14 (?1855), Saint-Saëns entered a new phase of composition. These are serious and ambitious works written on a large scale, showing the influence of Schumann. The quintet is one of his earliest cyclic compositions and the piano writing is thick and heavy, a texture that is also in evidence in the ‘Urbs Roma’ Symphony and in those pieces from the period which combine piano and harmonium (e.g. op.8).
Not all the works written in the 1850s and 60s are so ponderous, however: the First Piano Trio op.18 has moments of extreme delicacy (the ostinato in the second movement is characteristic) and the Symphony no.2 is a prime example of orchestral economy, fugal severity and cyclic unity. The first three piano concertos (also from the 1850s and 60s) are notable as early examples of the piano concerto in France. The second, still in the repertory, has a first movement that deviates from the typical sonata-form pattern; all three have frivolous finales which capture the prevailing mood of the Second Empire. The First Cello Concerto op.33 is a far more serious work. Its stormy opening movement has an allegro appassionato character, more so than the two later works which actually bear this title (opp.43, 70). Saint-Saëns's op.28 willingness to experiment with the traditional form of the concerto is evident here and elsewhere, and his first works of descriptive music also date from the 1860s. In the Introduction and Rondo Capriccioso for violin and orchestra he used idiomatic Spanish rhythms, and in later works of this type (the Havanaise and Caprice andalous) he alternated raised and lowered 7ths to create a wistful mood. La princesse jaune, his first opera to be performed (1872), employs pentatonic melodies, used earlier in the march Orient et occident, and initiated a spate of operas on Japanese themes by other composers. His other exotic works (the Nuit persane, Suite algérienne, Africa, the Fifth Piano Concerto and Souvenir d'Ismaïlia) are frequently in the minor mode with the sixth and seventh degrees raised, also showing a variety of other techniques. The Rapsodie d'Auvergne and the Caprice sur des airs danois et russes are based on European folksongs, as are portions of several other works. Furthermore, the virtuoso pedal technique of his early organ works, such as the Fantaisie (1857) and the Trois rhapsodies sur des cantiques bretons (1866), is thought to have influenced the symphonic style of late 19th-century French organ writing. In the 1870s Saint-Saëns composed four symphonic poems (Le rouet d'Omphale, Phaéton, Danse macabre and La jeunesse d'Hercule) in which he experimented with orchestration and thematic transformation. La jeunesse d'Hercule is modelled closely on Liszt, but the others concentrate on some physical movement – spinning, riding, dancing – which is described in musical terms. He had previously experimented with thematic transformation in his programmatic overture Spartacus and later used it in his Fourth Piano Concerto and the ‘Organ’ Symphony (no.3).
Some of Saint-Saëns’s best and most characteristic compositions date from the 1870s and 80s. These include the Fourth Piano Concerto, Third Violin Concerto, ‘Organ’ Symphony, Samson et Dalila, Le déluge, the Piano Quartet op.41, the First Violin Sonata, First Cello Sonata, Variations on a Theme of Beethoven and Le carnaval des animaux. Characteristic of many works written at this time is the use of repeated rhythmic motifs or of chorale melodies, combined in the second movement of the op.41 quartet. Both the Fourth Piano Concerto and the ‘Organ’ Symphony begin in C minor and end in C major employ thematic transformation and a chorale melody, and the four movements are arranged (as are those of the First Violin Sonata) in an interlocking pattern of two plus two. Saint-Saëns worked on Le carnaval des animaux concurrently with the ‘Organ’ Symphony and it remains his most brilliant comic work, parodying Offenbach, Berlioz, Mendelssohn, Rossini, his own Danse macabre and several popular tunes. The Third Violin Concerto (1880) is more rewarding musically and less demanding technically than the two earlier violin concertos; the chorale-like passage in B major near the end may have been influenced by his own Fourth Piano Concerto. A Morceau de concert for violin, written in the same year as the concerto, shares a number of affinities with it. Unlike his other Morceaux de concert (opp.94, 154), this piece is essentially a concerto first movement.
As an opera composer Saint-Saëns had an unerring sense for accurate declamation; in Samson et Dalila he also retained the identity of aria and ensemble, welding the whole work together with solid musical craftsmanship. Among his other operas, Etienne Marcel, Henry VIII (which has a principal theme based on a traditional English melody that Saint-Saëns found in the Buckingham Palace library) and Ascanio merit study and revival. The subjects he chose call for the flamboyant expertise of a Meyerbeer, and although the operas contain much agreeable and skilfully shaped music, they are deficient in theatrical effect. The success of Samson et Dalila can be attributed not least to its having originally been conceived as an oratorio, thereby enabling the composer to concentrate on purely musical aspects.
Saint-Saëns wrote songs throughout his career, setting the poetry of Lamartine, Hugo and Banville as well as his own verses. The style naturally varies with the subject, but many songs reveal his vivid pictorial sense and his gift for caricature.
Much of Saint-Saëns's piano music was written after 1870. Most of it is salon music (mazurkas, waltzes, albumleaves, souvenirs etc.); but the three sets of Etudes (opp.52, 111, 135) and the Variations on a Theme of Beethoven op.35 (piano duo) rank with the concertos. The Septet op.65 (1880) is, like the suites (opp.16, 49, 90), a neo-classical work that revives 17th-century French dance forms. Although these dances are rigid and less original than the pavanes and menuets antiques of Debussy and Ravel, they reflect Saint-Saëns's interest in the rediscovery and revival of the forgotten French musical tradition of the 17th century (his editions of Lully, Charpentier and Rameau date from this period).
Beginning with the Second Violin Sonata (1896), a stylistic change is noticeable in much of Saint-Saëns's music. The piano writing is generally more linear and less heavy, and there is a growing preference for the thin sonorities of the harp (as in the Fantaisie op.95 for harp, the Fantaisie op.124 for violin and harp and the Morceau de concert op.154 for harp and orchestra) and woodwind (as in Odelette op.162 for flute and orchestra and the solo sonatas for oboe, clarinet and bassoon opp.166–8). The two string quartets (opp.112, 153) mark the first elimination of the piano in his chamber works. Remote chord progressions and modal cadences become increasingly apparent, and the subjects of his stage works are almost exclusively Greek. This austere tendency is, of course, typical of many composers after World War I, but it serves to emphasize the classical aspect of Saint-Saëns's nature which, latent earlier, had seldom been displayed in such rarefied form. Saint-Saëns's oeuvre has been criticized as uneven; this is in part the result of both an unusual facility and his friendship with the publisher Auguste Durand, who was perhaps insufficiently critical. However, it is also diverse and multi-faceted.
Saint-Saëns's writings attest his wide tolerance on many musical issues and his concern for order, clarity and precision. Like the Parnassian poets, he was a proponent of ‘art for art's sake’, and his views on expression and passion in art conflicted with the prevailing Romantic aesthetic. In his memoirs, Ecole buissonnière, he wrote:
Music is something besides a source of sensuous pleasure and keen emotion, and this resource, precious as it is, is only a chance corner in the wide realm of musical art. He who does not get absolute pleasure from a simple series of well-constructed chords, beautiful only in their arrangement, is not really fond of music.
Although Saint-Saëns’s writings are remarkably consistent, it cannot be said that he evolved a distinctive musical style. Rather, he defended the French tradition that threatened to be engulfed by Wagnerian influences and created the environment that nourished his successors.