The Well-Tempered Clavier, Book I: Prelude No. 1

At a glance

• What it isthe first piece in Book I of the keyboard collection The Well-Tempered Clavier. Each prelude is paired with a fugue.
• Who, when, whyBach gathered the book in his Köthen years, dating its title page 1722, and wrote there that it was for young people eager to learn and for the pleasure of the already skilled.
• What to listen forchords spread in the same pattern every bar, and the large arc traced as the chords change.

Listen for

• The openinga C major chord unfolds from bottom to top, and the same pattern repeats once more. This pair continues in every bar.
• The middlethe harmony wanders off to distant keys, then one low note is held at length as tension builds.
• The endingthe pattern loosens and the final chord settles calmly back in C major.

When it was written

"Well-tempered" relates to the idea of tuning the octave so that all keys can be played without strain. Bach showed it by writing a prelude and fugue in each of the twenty-four major and minor keys. This first prelude had appeared earlier in a shorter form in a practice notebook for his eldest son, Wilhelm Friedemann.

About 130 years later, in 1853, the French composer Charles Gounod used this prelude as an accompaniment and laid a new melody on top. That became Gounod's widely sung "Ave Maria."