Musical Form
Prelude
A short introductory piece - that became a standalone form in its own right.
Solo / Keyboard
A prelude is, by original definition, a short piece that introduces something larger - in the Baroque era, most often paired directly with a fugue, functioning almost like a warm-up before the fugue's more rigorous counterpoint.
Improvised beginnings
The earliest preludes weren't written down at all. Lutenists and keyboard players improvised a few flourishes before a piece to check their tuning, loosen their fingers, and set the key for listeners. Some French harpsichord composers of the 17th century wrote these down as "unmeasured" preludes, with no bar lines at all, leaving the rhythm to the player's imagination.
Bach
Bach's Well-Tempered Clavier pairs a prelude and fugue in every key, and each prelude has its own distinct character despite its introductory role - some flowing, some dancing, some almost improvisatory. He also wrote preludes to open his cello and keyboard suites, organ preludes paired with fugues, and chorale preludes, short organ pieces built on a hymn tune that would introduce the congregation's singing.
The prelude stands alone
By the Romantic era, composers had detached the prelude from anything it was supposed to introduce, treating it instead as a complete, standalone character piece - usually brief, often exploring a single mood or technical idea. Chopin's 24 Preludes, Op. 28, are the clearest example: each one is self-sufficient, with nothing following it. Some last less than a minute. The 15th is nicknamed the "Raindrop," for the repeated note that falls through it like rain, and two of the set were played at Chopin's own funeral.
Both Bach and Chopin organized their sets the same structural way, moving through all 24 major and minor keys, a nod back to the prelude's Baroque role as a showcase for playing comfortably in any key. Alexander Scriabin, Rachmaninoff, and Shostakovich all followed with sets covering every key.
Debussy's two books of Preludes, written some seventy years after Chopin's, keep the short, self-contained format but add evocative titles ("The Sunken Cathedral," "Footsteps in the Snow") that Debussy pointedly printed only at the end of each piece, so the music would suggest its own image before the listener saw the name. George Gershwin's three jazzy Preludes for piano (1926) are another favorite.
The orchestral prelude
The word also turns up in the opera house: Wagner and Verdi often opened their operas with a prelude that flows straight into the first scene, rather than a separate overture.
Famous preludes
- Bach - Prelude in C major, The Well-Tempered Clavier, Book 1.
- Chopin - Prelude in E minor, Op. 28 No. 4, and the "Raindrop," No. 15.
- Rachmaninoff - Prelude in C-sharp minor (1892).
- Debussy - "The Girl with the Flaxen Hair" and "The Sunken Cathedral."
- Gershwin - Three Preludes (1926).
Where to start listening: Bach's Prelude in C major (from the Well-Tempered Clavier, Book 1) is deceptively simple and widely recognizable; Chopin's Prelude in E minor, Op. 28 No. 4, shows the Romantic-era standalone version. Then listen to all 24 Chopin preludes in one sitting - it takes about forty minutes.