The Romantic era created the concept of tonality to describe the haromic vocabulary which they inherited from the baroque and classical periods. And sought to fuse the chromatic innovations with the large structural harmonic planning of Franz Joseph Haydn, Wolfgang Amadeus Mozart and Ludwig van Beethoven. This was, in particular, to satisfy the desire for a greater fluidity of movement, greater contrast and, in the end, longer works. Chromaticism grew more frequent and varied in use, as did dissonance. Composers modulated to increasingly remote keys. Modulations were not always as extensively prepared as they were in the classical era, and sometimes instead of a pivot chord, a pivot note was used. Franz Liszt and others sometimes enharmonically "spelled" this note in a different way (for example, changing a C sharp into a D flat) to modulate into even more distant keys. The properties of the dimished seventh chord, which enables modulation to almost any key, were also extensively exploited. Composers such as Ludwig van Beethoven, often regarded as the first Romantic composer, and later Richard Wagner expanded their harmonic language to include chords previously unused, or to treat existing chords in different ways. Wagner's Tristan chord, found in Tristan and Isolde, has had much written about it attempting to explain exactly what harmonic function it serves.
Romantic music analogized music to poetry and to rhapsodic and narrative structures, and at the same time created a more systematic basis for teaching the composing and performing of concert music. The Romantic era codified previous practice, for example inventing the idea of the sonata form, and then almost immediately began to extend that form. There was an increasing focus on melodies and themes, as well as an explosion in composing songs. This emphasis on melody found expression in the more and more extensive use of cyclic form, which turned out to be an important structural device to unify the much longer pieces which were composed in the Romantic era.
These trends — towards greater harmonic elusiveness and fluidity, longer and more powerfully placed melodies, poesis as the basis of expression, mixing of literature and music — were all present to one degree or another previously; however, the Romantic Era made their pursuit central to the idea of music itself. Technology also played a significant role in the changes in musical language — from the increasing range and power of the piano, to the introduction of valves and keys for instruments, the very sound and reach of the symphony orchestra changed, and with it the kinds of works which were possible.





