Instrumental Music 1700–1820: Two Worlds, Two Set Works

Two Worlds, One Area of Study

The phrase ‘Instrumental Music 1700–1820’ hides a huge amount of change inside one label. At the start of this period, composers such as J S Bach were writing for small courts and churches, using continuous bass lines and blocks of contrasting sound. By the end of the period, Beethoven was writing music for a solo instrument — the piano — that could whisper and roar within the same phrase, leaving the confined world of the palace chamber behind.

This area of study asks you to understand both ends of that journey through two contrasting set works: the third movement of Bach’s Brandenburg Concerto No. 5 in D major, representing the late Baroque concerto grosso, and the first movement of Beethoven’s Piano Sonata No. 8 in C minor, the ‘Pathétique’, representing the Classical sonata pushed toward Romantic expression. Knowing what each piece is for, and who it was written for, explains almost every musical decision inside it.

The Late Baroque World: Concerto, Ritornello and Patronage

Baroque instrumental music grew out of patronage — composers were employed by courts, churches or wealthy patrons to supply music for specific occasions, and Bach wrote his six Brandenburg Concertos as a job application of sorts, dedicating them to the Margrave of Brandenburg in 1721. A concerto grosso sets a small group of soloists, the concertino, against a larger body of strings, the ripieno. The two groups are not equal in weight but in conversation: the ripieno often plays sturdy, chordal material while the concertino weaves quicker, more decorated lines above and around it.

Baroque orchestras had no gradual crescendo pedal or dial to turn; instead they moved abruptly between loud and soft blocks of sound, a device known as terraced dynamics. Underneath almost everything sits the continuo — typically harpsichord and cello or bass instrument — providing a constant harmonic and rhythmic foundation, filling out chords from a bass line and figured numbers (figured bass) rather than a fully written-out part. This is music built from repeating structural units rather than long melodic development.

Set Work Spotlight: Bach’s Brandenburg Concerto No. 5, Third Movement

Brandenburg Concerto No. 5 is unusual because its concertino is flute, violin and harpsichord, with the harpsichord treated almost as a solo instrument in its own right rather than merely providing continuo — a genuinely progressive move for 1721. The finale is a lively gigue in da capo (A–B–A) form, built largely from imitative entries: a nimble, dance-like idea is passed in turn between flute, violin and harpsichord, each restating it slightly differently, while the ripieno strings punctuate with short tutti interjections that feel like a ritornello returning.

As you listen, follow the imitation: try to catch the same short motif arriving first in one instrument, then chasing itself into the next. Notice how the harpsichord, freed from just accompanying, gets genuinely virtuosic passagework, and how the texture thins to soloists alone before the full ensemble reassembles. That alternation between small and large groups, decorated melody and firm bass, is the concerto grosso in miniature.

Listening with a performance in front of you, follow the three soloists in constant dialogue as the imitative lines overlap, and the moment the ripieno strings step back in to close each section — a visual reminder that Baroque ensembles were small, close-knit teams rather than a large symphony orchestra.

The Classical World Turns Romantic: Sonata Form and the Fortepiano

By Beethoven’s time, the driving structural idea was no longer the returning ritornello but sonata form: an exposition presents a first subject in the home key and a contrasting second subject in a related key, a development reworks and destabilises that material through distant keys, and a recapitulation restores both subjects, now usually both in the home key, giving a satisfying sense of resolution. Classical phrasing favours clear, balanced four-bar units — question-and-answer shapes that feel symmetrical, even when Beethoven bends them.

The instrument itself was changing fast. The fortepianos of Beethoven’s early career had a lighter tone and narrower dynamic range than a modern concert grand, but across his lifetime instrument builders extended the keyboard’s range and strengthened its frame, letting composers demand real fortissimos and true pianissimos rather than Baroque-style terraced blocks. Beethoven pushed performers and instrument makers alike, writing dynamic markings, sudden accents and pedal effects that stretch what an early fortepiano could do — an early sign of Romantic expressive extremes to come.

Set Work Spotlight: Beethoven’s Pathétique Sonata, First Movement

The first movement of the Piano Sonata No. 8 in C minor, Op. 13, opens with a slow Grave introduction of grinding, dissonant chords and a dotted rhythm — a dramatic gesture unusual for a Classical sonata opening — before launching into an urgent Allegro di molto e con brio built in sonata form. Its agitated C minor first subject contrasts with a second subject that begins in the more unexpected E flat minor before brightening into E flat major partway through, though Beethoven keeps unsettling it with syncopation and sudden dynamic shifts.

Listen for the way the Grave material unexpectedly interrupts the movement again, both just before the development proper and near the very end of the movement, as if the slow introduction refuses to be left behind — a structural surprise that goes beyond standard Classical sonata form. Also track the extremes of dynamic and register: crashing low bass octaves against delicate treble filigree, demanding far more from the fortepiano’s expressive range than Bach could ever have asked of a harpsichord.

As you listen, notice the intensity — sudden fortissimo chords, rapid scalic and arpeggio passagework, and pedalled resonance sustaining the brooding Grave chords — all evidence of a composer treating the piano as an instrument of raw emotional power rather than polite Classical elegance.

Where We Go Next

You now have the big picture: a Baroque concerto grosso built from ritornello form, terraced dynamics and continuo, written for a patron; and a Classical-into-Romantic piano sonata built from sonata form, exploring the newly expanded dynamic range of the fortepiano. The next two lessons in this unit go inside each set work in far greater depth — first Bach’s Brandenburg Concerto No. 5, then Beethoven’s Pathétique — examining texture, harmony, tonality and structure bar by bar, so keep this overview as your map for what follows.