With his third symphony (op. 52) Sibelius left Late Romanticism behind and moved towards a Neo-Classicist musical language and mode of expression. Thereafter, towards 1910, his style began to display more and more aspects of modernism and expressionism. This trend culminated in the string quartet Voces intimæ (op. 56) and the fourth symphony (op. 63). Even before this, the songs Jubal and Teodora, which were composed in 1908 (op. 35 nos. 1 and 2), reflect the same development. Jubal (based on a poem by Ernst Josephson), is often described as rhapsodic, presumably because of the voice part and the apparently free, recitative-like alternation of the Giusto sequences. The structure of the song is nevertheless very clear-cut. This is not the case with the passionate and exotic Teodora (song no. 2). Teodora differs from Sibelius's other songs both in its musical style and its themes. Bertel Gripenberg's exotic, "decadent" poem inspired Sibelius to an exceptionally sensuous and erotic manner of expression. This is conveyed both in the vocal part, which is at times close to almost pure recitative (four years before Schoenberg's Pierrot lunaire), and by the rolling dissonant arpeggios of the piano part. Teodora is one of the most "modern” of Sibelius's solo songs.

Opus 57
In 1909 Sibelius spent April and May in Berlin, where he put the finishing touches to his string quartet Voces intimæ. After completing the work he continued to fulfil the contract he had signed with the publisher Robert Lienau, composing the song collection opus 57 to poems by Ernst Josephson. The texts for the eight songs of the collection differ greatly from each other, as do Sibelius's settings of them. The collection both begins and ends with an unpredictable expressionistic song: Älven och snigeln (no. 1) and Näcken (no. 8). Between these we have En blomma stod vid vägen (no. 2), which resembles a folk song, and Kvarnhjulet (no. 3), which is divided into two very different sections (con moto and tranquillo). The tragic, introvert atmosphere in these songs culminates in the fifth song of the collection, Jag är ett träd. Before this, however, there is the lighter Maj (no. 4), which follows the German lied tradition. In the song Hertig Magnus (no. 6) Sibelius returns to a theme which is familiar from the song Under strandens granar and from Koskenlaskijan morsiamet (The Rapids-Shooter's Brides): the struggle between the water sprite and man. The poem Vänskapens blomma (no. 7) induced Sibelius to write two versions which differ considerably from each other. Thus there is a somewhat monotonous version in Late Romantic style, which the composer rejected. The one he actually chose for the collection is more Neoclassical and vigorous in style.

After completing opus 57 in Berlin, Sibelius wrote in his diary: "I have to get home. I cannot work here anymore. A change in style?" In the song Hymn to Thaïs, the Unforgettable (words by Arthur Borgström) the stylistic transition is already evident. The introspection and gloom which had marked opus 57 are gone. In this song modality introduces itself in an impressionistic guise. The song was rescued from oblivion in the late 1940s, when Sibelius dedicated it to the soprano Aulikki Rautavaara.

Opus 61
Sibelius composed his song collection opus 61 one year after the previous collection, in June-July 1910. These eight songs, too, are experimental, just as the Josephson songs of the previous collection had been. However, instead of displaying expressionistic tendencies the songs are connected with a Late Romantic and at times impressionistic musical landscape. Once again, the collection is very heterogeneous. The suite begins with Långsamt som kvällskyn (no. 1; words by K. A. Tavaststjerna). As Erik Tawaststjerna put it, "The composer has absorbed the pathos of Rachmaninov and given it a more austere Nordic colour." In the piano part of the impressionistic Vattenplask (no. 2; words by Rydberg) Sibelius subtly imitates the lapping of the waves, whereas När jag drömmer (no. 3; words by Tavaststjerna) ends with a piano tremolo imitating the nightingale. Romeo, a gentle parody of the balcony scene in Romeo and Juliet (no. 4; words by Tavaststjerna), is based on the subtle variation of a single melodic phrase. Sibelius later constructed the song Hennes budskap a slightly similar way. For song no. 5, Romance (no. 5; words by Tavaststjerna), Sibelius borrowed the Phrygian melodic-harmonic idea of Hymn to Thaïs. It seems to have been this feature that led Sibelius to dedicate the song to Artur Borgström. In Dolce far niente (no. 6) there is a contrast between the spritely main theme and the middle section, with its echoes of Wagner's Tristan. The treatment seems to underline the anguish connected with time frittered away in sweet idleness. The piano part in the best-known song of the collection, Fåfäng önskan (no. 7; words by Runeberg), is dominated by Chopinesque torrents of arpeggios. The collection ends with one of Sibelius's many songs with a spring motif, Vårtagen (no. 8; words by Bertel Gripenberg). Despite the expressionistic extremes of the text the song is pleasant and merry, as Robert Keane has pointed out.

Opus 72After completing opus 61 Sibelius composed no solo songs for several years. The songs of the following collection, opus 72, were written gradually during the years 1914-15 (with the exception of the Runeberg song Hundra vägar, which probably dates from 1907). Apart from the songs of opus 17, this is the most heterogeneous of Sibelius's song collections: not only were the songs written at different points of time, but the texts are in three different languages, Swedish, German and Finnish. The songs also differ stylistically from each other. For example, Der Wanderer und der Bach (no. 5; words by Martin Greif), which has something in common with Schubert's "wanderer" songs, and also the Runeberg song Hundra vägar (no. 6), both hark back stylistically to Sibelius's early songs. By contrast, the passionate and impressive Kyssen (no. 3; words by Viktor Rydberg) returns to the landscape of the songs from the turn of the century. It is only the fourth song, Kaiutar (The Echo-Nymph), that represents the "modern" side of Sibelius. The text for Kaiutar was written by Sibelius's schoolmate Karl Gustav Larson (later called Kaarlo Kyösti Larson, or Larin-Kyösti). It uses Kalevala-like phrases to describe the birth of Echo. Interestingly, Sibelius's song does not go back to his Romantic Kalevala-influenced style; in fact, the style is mainly impressionistic. The collection as we now have it is incomplete. The first two songs of the opus, Vi ses igen (words by Viktor Rydberg) and Orions bälte (words by Zacharias Topelius), disappeared on the eve of the First World War in 1914, when the German publisher Breitkopf & Härtel sent the original manuscripts of the songs to England for translation