Describe the fundamental differences in harmonic language between the Baroque and Romantic periods, providing specific examples of chord progressions and voice leading techniques characteristic of each era.

The fundamental differences in harmonic language between the Baroque and Romantic periods are significant, reflecting shifts in musical aesthetics, compositional techniques, and the expressive aims of composers.

In the Baroque period (roughly 1600-1750), harmony was largely governed by the principles of tonal functional harmony. Chord progressions were primarily diatonic, meaning they were based on the major and minor scales and their related harmonies. The dominant-tonic relationship was paramount, providing a strong sense of resolution and closure. Common chord progressions included the movement from the subdominant (IV) to the dominant (V), then to the tonic (I), and various other permutations based on the circle of fifths. Voice leading was carefully controlled, emphasizing stepwise motion and the avoidance of parallel fifths and octaves. Bass lines were foundational, often creating a strong sense of harmonic direction. Cadences, such as the authentic (V-I) and plagal (IV-I) cadences, played crucial roles in shaping the musical structure. For example, in a typical Baroque piece, we might encounter a simple progression such as I-IV-V-I in C major (C-F-G-C), used to provide a clear sense of tonal grounding. Diminished and secondary dominant chords were used to add color, however, these were handled within a strict tonal framework. The harmonic rhythm in Baroque music was often fairly consistent, with changes occurring at regular intervals, often every measure or two.

The Romantic period (roughly 1820-1900) saw a move towards more complex and expressive harmonic language. While the tonal system remained the foundation, composers pushed its boundaries by introducing more chromaticism, altered chords, and non-functional harmonies. The strong emphasis on the dominant-tonic relationship of the Baroque era became less rigid. Composers began to exploit the expressive qualities of dissonance more prominently. They experimented with altered dominants, diminished seventh chords, and augmented chords to create tension and drama. Modulation to remote keys became frequent, creating a sense of instability and emotional intensity. Voice leading became more fluid, sometimes featuring leaps rather than stepwise motion. Harmonic rhythm often became more varied and unpredictable, changing more frequently to create moments of heightened intensity or repose. Composers often employed extended chords (ninths, elevenths, and thirteenths) to add richness and complexity. Pedal points were also used to create tension. An example of a Romantic harmonic progression might involve a movement from a dominant seventh to a Neapolitan chord followed by an augmented chord, and finally, a delayed resolution to the tonic. This progression shows a higher degree of chromaticism than is commonly found in Baroque music. For example, in a piece by Chopin, you might see a passage that begins in C minor and travels through several chromatic modulations before returning, and it is not necessarily done in a strict diatonic way but rather follows the emotional flow. Wagner's works often exemplify the use of chromaticism and non-functional harmonies, pushing the boundaries of tonal harmony in a more extreme manner, by using techniques such as the Tristan chord which does not have a resolution in a classical sense, but rather is used as an unresolved tension. In summary, Baroque harmony is characterized by clear diatonic functionality, emphasis on dominant-tonic relationships, and consistent voice leading. Romantic harmony is characterized by chromaticism, increased dissonance, more frequent modulations to remote keys, a more varied harmonic rhythm, and emphasis on expressive qualities. The move from the structured and balanced sound world of the Baroque to the more emotionally charged and dramatic sound world of the Romantic period is reflected in the different approaches to harmony during these eras.