umber of strings were placed side by side,
and a mechanism inserted which, by pressing a key (_clavis_),
would move the bridge to the point at which the string must
divide to give the note indicated by the key. This made it
possible to use one string for several different notes, and
explains why the clavichord or clavicembalo needed comparatively
few strings. This instrument became obsolete toward the end
of the eighteenth century.

The other species of instrument, the harpsichord, which was
invented about 1400, and which may be considered as having
sprung from the clavichord, consisted of a separate string for
each sound; the key, instead of setting in action a device
for striking and at the same time _dividing_ the strings,
caused the strings to be plucked by quills. Thus, in these
instruments, not only was an entirely different quality of tone
produced, but the pitch of a string remained unaltered. These
instruments were called _bundfrei_, "unbound," in opposition to
the _clavicembalo_, which was called _gebunden_, or "bound." The
harpsichord was much more complicated than the clavichord,
in that the latter ceased to sound when the key which moved
the bridge was released, whereas the harpsichord required what
is called a "damper" to stop the sound when the key came up;
once the string was touched by the quill, all command of the
tone by the key was lost. To regulate this, a device was added
to the instrument by means of which a damper fell on the string
when the key was released, thereby stopping the sound.

We have now to consider the instrumental development of the
Middle Ages.

An instrument of the harpsichord family which has significance
in the development of the instruments of the Middle Ages is
the spinet (from _spina_, "thorn"; it had leather points up
to 1500), first made by Johannes Spinctus, Venice, 1500. It
was a harpsichord with a _square_ case, the strings running
diagonally instead of lengthwise. When the spinet was of
very small dimensions it was called a virginal; when it was
in the shape of our modern grand piano, it was, of course,
a harpsichord; and when the strings and sounding board
were arranged perpendicularly, the instrument was called
a clavicitherium. As early as 1500, then, four different
instruments were in general use, the larger ones having a
compass of about four octaves. The connecting link between the
harpsichord, the clavichord, and the piano, was the dulcimer or
hackbrett,