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, which was a tavern instrument. Pantaleon Hebenstreit, a dancing master and inventor of Leipzig, in 1705 added an improved hammer action, which was first applied to keyboard instruments by Cristofori, an instrument maker at Florence (1711). His instrument was called _forte-piano_ or _pianoforte_, because it would strike loud or soft. These instruments all descended from the ancient lyre, the only difference being that instead of causing the strings to vibrate by means of a plectrum held in the hand, the plectrum was set in motion by the mechanism of the _claves_ or keys. The system of fingering employed in playing the harpsichord, up to 1700, did not make use of the thumb. J.S. Bach, F. Couperin, and J.P. Rameau were the pioneers in this matter. The first published work on piano technique and fingering was that by C.P.E. Bach (1753).