A clavier refers to a stringed keyboard musical instrument from the late 17th century. Harpsichords, clavichords and later pianos sometimes took on the name "clavier." The word clavier also became the inspiration for a piece written by Johann Sebastian Bach, called the "Well-Tempered Clavier," a piece that exemplifies the style of the late Baroque period. The piece contains fugues with a variety of subjects, textures, forms and treatments. Musicians frequently play Bach's piece on clavichords, harpsichords, pianos and organs. Bach used the title "Well-Tempered" because the term refers to a keyboard instrument perfectly tuned to permit music written in any of 24 possible keys to sound good. Bach's piece traverses all 24 keys, and the piece requires that specific degree of tuning to play the piece well.