Frederick Chopin composed his Preludes as short piano pieces written between 1834–39 and intended as explorations of the characters of various keys. The earlier examples of such works are those of J. S. Bach appearing in his Well Tempered Clavier, much of which was composed in the 1720’s. Early 19th-century composers like Chopin returned to the idea in more flexible form.
When Chopin decided to write some preludes of his own in the 1830’s, he took a more relaxed approach than had Bach. The German Baroque master had written one prelude in each of the major and minor keys, and then matched each with a complementary fugue, for a total of 48 individual pieces. Chopin wrote preludes only, without the greater intricacy of accompanying fugues, resulting in 24 individual pieces that were published together in 1839.
Here is Grigory Sokolov, performing the Prelude Op. 28 number 4, and — for me— expressing the sadness of our times as we shelter in place:
