.
As music grew more and more complex, and especially as writing in several parts came into use (cf. rise of organum, descant, and counterpoint), it became increasingly difficult to express musical ideas on the basis of the old notation, and numerous attempts were made to invent a more accurate and usable system. Among these one of the most interesting was that in which the words of the text were written in the spaces between long, parallel lines, placing the initial letters of the words tone and semi-tone at the beginning of the line to indicate the scale interval. An example will make this clear.
This indicated the precise melodic interval but did not give any idea of the rhythm, and the natural accents of the text were the only guide the singer had in this direction, as was the case in neume-notation and in early staff-notation also. Various other attempts to invent a more definite notation were made, but all were sporadic, and it was not until the idea of using the lines (later lines and spaces) to represent definite pitches, and writing notes of various shapes (derived from the neumae) to indicate relative duration-values—it was only when this combination of two elements was devised that any one system began to be universally used.
Just how the transition from neume to staff notation was made no one knows: it was not done in a day nor in a year but was the result of a gradual process of evolution and improvement. Nor is it probable that any one man deserves the entire credit for the invention of staff notation, although this feat is commonly attributed to an Italian monk named Guido d'Arezzo (approximate dates 995-1050). To this same monk we are indebted, however, for the invention of the syllables (UT, RE, MI, etc.) which (in a somewhat modified form) are so widely used for sight-singing purposes. (For a more detailed account of the transition to staff notation, see Grove, op. cit. article notation.) It will now be readily seen that our modern notation is the result of a combination of two preceding methods (the Greek letters, and the neumes) together with a new element—the staff, emphasizing the idea that higher tones are written higher on the staff than lower ones. The development of the neumes into notes of various shapes indicating relative time values and the division of the staff into measures with a definite measure signature at the beginning are natural developments of the earlier primitive idea. In the system of "musica mensurabilis" or measured music which was inaugurated a little later, the virga (which had meanwhile developed into a square-headed neume) was adopted as the longa or long note, and the punctus in two of its forms as breve and semi-breve (short and half-short). The longa is now extinct, but the modern form of the breve is still used as the double-whole-note, and the semi-breve is our modern whole-note.
Red-colored notes were sometimes used to indicate changes in value and before long outline notes (called empty notes) came into use, these being easier to make than the solid ones. The transition from square- and diamond-shaped notes to round and oval ones also came about because of the greater facility with which the latter could be written, and for the same reason notes of small denomination were later "tied together" or stroked. This latter usage began about 1700 A.D.
It is interesting to find that when "measured music" was finally inaugurated there were at first but two measure-signatures, viz.—the circle, standing for three-beat measure (the so-called perfect measure) and the semi-circle (or broken circle) which indicated two-beat measure. Occasionally three-beat measure was indicated by three vertical strokes at the beginning of the melody, while two-beat measure was shown by two such strokes. Upon the basis of these two varieties of measure, primitive in conception though they may have been, has been built nevertheless the whole system now employed, and in the last analysis all forms of measure now in use will be found to be of either the two-beat or the three-beat variety. The circle has disappeared entirely as a measure-sign, but the broken circle still survives, and from it are derived the familiar signs
