CLAVICYTHERIUM, a name usually applied to an up right spinet (q.v.), the soundboard and strings of which were vertical instead of horizontal, being thus perpendicular to the keyboard; but it would seem that the clavicytherium proper is distinct from the upright spinet in that its strings are placed horizontally. In a unique specimen with two keyboards dating from the 16th or 17th century, which is in the collection of Baron Alexandre Kraus, what appear to be vibrating strings stretched over a soundboard perpendicular to the keyboard are in reality the wires forming part of the mechanism of the action. The instrument was probably of Italian or possibly South German origin and it may be noted that its name has also been applied at times to the upright harpsichord.
There is a very fine specimen of the so-called clavicytherium (really an upright spinet) in the Donaldson museum of the Royal College of Music, London, acquired from the Correr collection at Venice in 1885.
For the history of the clavicytherium considered as a forerunner of the pianoforte, see PIANOFORTE.