In the 12th and 13th centuries, the clavichord evolved from the Greek monochord, an instrument that consisted of a soundboard above which a string was stretched and divided into the desired lengths by means of a moveable bridge. A more developed form was the polychord, which was fitted with several strings to allow for the simultaneous production of more than one note. The addition of keys to the instrument heralded the birth of the clavichord. With his knowledge of music history, Friedrich Gulda was of course aware that the clavichord was Bach's favorite instrument alongside the organ and so it seemed fitting for him to perform Bach's works on the clavichord. The first part of this recording presents Gulda playing a Widmayer clavichord, which has an intimate, refined sound, whereas the second part features a Neupert, which sounds more like a concert instrument.