The earliest known record of the clavichord occurs in some rules of the minnesingers, dated 1404, preserved at Vienna. (See Ambros, Geschichte der Musik [1892], ii. 226.) The monochord is named with it, showing a differentiation of these instruments, and of them from the clavicimbalum—the keyed cymbal, cembalo (Italian), or psaltery. From this we learn that a keyboard had been thus early adapted to that favourite mediaeval stringed in strument, the "cembalo" of Boccaccio, the "sautrie" of Chaucer.
There were two forms of the psaltery : (I) the trapeze, one of the oldest representations of which is to be found in Orcagna's famous Trionfo della Morte in the Campo Santo at Pisa, and another by the same painter in the National Gallery, London ; and (2) the contemporary "testa di porco," the pig's head, which was of triangular shape as the name suggests. The trapeze psaltery was strung horizontally, the "istromento di porco" either hori zontally or vertically—the notes, as in the common dulcimer, being in groups of three or four unisons. In these differences of form and stringing we see the cause of the ultimate differenti ation of the spinet and harpsichord. The compass of the psalteries was nearly that of Guido's scale; but according to Mersenne (L'Harmonie universelle [Paris, 1636], livre p. 107), the low est interval was a fourth, G to C, which is worthy of notice as anticipating the later "short measure" of the spinet and organ.
The simplicity of the clavichord inclines us to place it, in order of time, before the clavicimbalum or clavicembalo ; but we do not know how the sounds of the latter were at first excited. There is an indication as to its early form to be seen in the church of the Certosa near Pavia. In 1472, chromatic keyboards, which imply a considerable advance, were already in use. There is an authen tic representation of a chromatic keyboard, painted not later than 1426, in the St. Cecilia panel (now at Berlin) of the famous Adoration of the Lamb by the Van Eycks. The instrument de picted is a positive organ, and it is interesting to notice in this realistic painting that the keys are evidently boxwood, as in the Italian spinets of later date, and that the angel plays a common chord—A with the right hand, F and C with the left. But diatonic organs with eight steps or keys in the octave, which included the B flat and the B natural, as in Guido's scale, were long preserved, for Praetorius speaks of them as still existing nearly two hundred years later. This diatonic keyboard, we learn from Sebastian Virdung (Musica getutscht and auszgezogen, Basel, 1511), was the keyboard of the early clavichord. We reproduce his diagram as
the only authority we have for the disposition of the one short key.
Virdung's diagram of the chromatic is the same as our own familiar keyboard, and comprises three octaves and a note, from F below the bass stave to G above the treble. But Virdung tells us that even then clavichords were made longer than four octaves by repetition of the same order of keys. The introduction of the chromatic order he attributes to the study of Boetius, and the consequent endeavour to restore the three musical genera of the Greeks—the diatonic, chromatic and enharmonic. But the last named was not attained until equal temperament tuning was de veloped by J. S. Bach. Virdung gives woodcuts of the clavi chordium, the virginal, the clavicimbalum and the clavicytherium. We reproduce three of them (figs. 3, 6 and 8), omitting the vir ginal as obviously incorrect. Writers on musical instruments have continually repeated these drawings without discerning that in the printing they are reversed, which puts the keyboards entirely wrong, and that in Luscinius's Latin translation of Virdung (Mu surgia, sive praxis musicae, Strasbourg, 1536), which has been hitherto chiefly followed, two of the engravings, the clavicim balum and the clavicytherium, are transposed, another cause of error.
Still commonly known as monochord, Virdung's clavichord was really a box of monochords, all the strings being of the same length. We observe in this drawing (fig. 3) the short sound board, which always remained a peculiarity of the clavichord, and the straight sound-board bridge—necessarily so when all the strings were of one length. To gain an angle of incidence for the tangents against the strings the keys were splayed, an expedient further rendered necessary by the "fretting"—three tangents being placed to give three different notes from each single group of strings tuned in unison. In the drawing the strings are merely indi cated. The German for fret is Bund, and such a clavichord, in that language, is known as a "gebundenes Clavichord" both fret (to was now able to produce, in '722, Das wohltemperirte Clavier, his famous collection of preludes and fugues in all the twenty-four major and minor scales for a clavichord which was tuned to what is now known as "equal temperament." The oldest clavichord, here called manicordo (as French inani corde, from monochord), known to exist is that shown in fig. 4.