Harpsichords were very important in music from the Renaissance and Baroque periods. They were used as solo instruments as well as to accompany an orchestra. Some of the most famous composers of harpsichord music are William Byrd (1543-1623), François Couperin (1668-1733), Domenico Scarlatti (1685-1757) and Johann Sebastian Bach (1685-1750). The last of these composers wrote "The Well-Tempered Clavier", which has a prelude and fugue in every major and minor key. It is said that Bach wrote this collection of music to show how keyboard instruments like the harpsichord can be tuned in a way to make playing in any key possible.