Around the middle of the twelfth century we find the keyed monochord, which was developed further, several strings being added, until eventually we recognize the clavichord. A tangent was fitted to the back of each key, which when raised contacted the single string, and facilitated simultaneous notes. The tangent acted as a bridge determining the speaking length of the string. A mute was fitted to the non-speaking length, so when the key was released the note stopped singing.
