Prelude
A prelude (Medieval Latin “praeludium”, a playing beforehand) is an instrumental piece with an opening or leading-in character and a formally free design. It often comes before a fugue, but it can also stand alone. The archive holds the Prelude in C major from Bach’s Well-Tempered Clavier, Book I.
- Word origin
- Medieval Latin praeludium, from Latin praeludere, “to play beforehand”
- Meaning
- introductory instrumental piece in free form
- In the archive
- Prelude in C major, The Well-Tempered Clavier I, No. 1, BWV 846
- Time signature of the archive piece
- C (4/4), 35 bars on 2 pages
An introduction in free form
The word has three meanings: a musical introduction, often freely improvised, for instance on the organ before the congregation sings; also an independent instrumental composition like a fantasia; and finally an introductory piece of music for lute and keyboard instruments in a formally free design, often combined with a fugue. As an instrumental work the prelude has an opening or leading-in character. Originally it was a formless, improvised introduction for organ or plucked instruments; in the 17th century it often opened a suite or sonata and later, as a form of its own, preceded a fugue, a fantasia or another work.
Bach’s “Well-Tempered Clavier” is a collection of preludes and fugues in two books, each with 24 pairs in all twelve major and minor keys. Each pair has its own BWV number; the first pair, with the Prelude in C major, bears the number 846, as the archive sheet also states.
Layout in the archive piece
The archive sheet shows only the prelude, without its fugue. The table divides it by bars. What stands out is how little the picture changes: from bar 1 to 32 the same rhythmic pattern appears in every bar on the sheet, and only the last bars differ. There are no repeat signs and no sections with headings of their own on the sheet; the piece follows a single plan.
| Bars | What the score shows |
|---|---|
| 1 to 32 | the same rhythmic pattern in every bar: in the right hand twice an eighth rest followed by six sixteenth notes; in the left hand the notes are struck anew twice per bar |
| 33 and 34 | running sixteenth notes in the right hand; in the bass the low C is held |
| 35 | a final chord with a fermata; before it comes the wavy line of the arpeggio |
A bar made of two equal halves: broken chord (our own example)
An example of our own with the same plan as the archive piece, but with different notes: each half of the bar consists of an eighth rest and six sixteenth notes, that is, of eight sixteenth notes or two beats. The notes of the chord are played one after another; bars 1 and 3 contain the notes C, E and G, bar 2 the notes D, G and B. Below lies a bass note.
The ending: arpeggio and fermata
A chord over a bass of C and the C an octave above, played as an arpeggio: the notes enter one after another from the bottom up and all ring on until the end. The fermata lengthens the chord beyond its written value. This is also how the archive piece ends, there with the wavy line before the chord and the fermata above it.
The first line shows the plan with notes of our own. The rest at the beginning of each half bar is part of the pattern: it gives the pulse some air before the notes enter. In the ending on the second line you see how an arpeggio and a fermata end the piece.
Bach’s prelude in the archive
Piano
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Präludium C-Dur Johann Sebastian Bach (1685–1750), The Well-Tempered Clavier I, No. 1, BWV 846 · piano · 2 pages
Time signature C, no sharps or flats in the key signature, 35 bars: page 1 carries bars 1 to 18, page 2 bars 19 to 35. The sheet contains only the prelude, no fugue. Bar 1 begins in the right hand with an eighth rest, followed by sixteenth notes; in the left hand a bass note enters on beat one. The last bar has a chord with a fermata and, in the bass, C and the C an octave above.
Distinctions
A prelude is not the same as a fugue, even though the two form a pair in the “Well-Tempered Clavier”. The combination with a fugue is frequent, but not universal. The introductory piece of an opera, by contrast, can be called a prelude or an overture.
Common mistakes
- Leaving out the eighth rest: If you start on the note at once, you shift the whole pattern by an eighth note.
- Cutting the bass notes short: In the left hand notes are joined by ties; they ring longer than the first attack suggests.
- Taking the sheet for the whole pair: The fugue belonging to this prelude is not on this sheet.
Continue on Maikstrings
Related terms
VorspielOvertureFantasiaArpeggioFermataPedal pointSixteenth noteSixteenth restFour-four timeC major
Editor: Maik Krohm · reviewed on 3 October 2026
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