In the period now under consideration (from the third to the tenth century), music was noted in this way:  an upstroke of the pen meant a raising of the voice, a downstroke lowered it, a flat stroke meant a repetition of the same note, thus [/ \ -] [G:  c’ g’ c’ c’].  Gradually it became necessary to indicate the contour of the melodies with more accuracy; therefore the circumflex was added [Over-slur] [G:  g’ c’’ g’] and reversed [Under-slur] [G:  g’ e’ g’].  Still later a sign for two steps was invented [Step] [G:  e’ g’ b’] and when the progression was to be diatonically stepwise the strokes were thicker [Thick Step] [G:  g’ a’ b’].  So this notation developed, and by combining the many signs together, simple non-rhythmic melodies could be indicated with comparative clearness and simplicity.  The flat stroke for a single note [-], indicating [G:  b’], eventually became smaller and thicker, thus [Thick -].  By combining these different signs, a skip of a third and back came to be noted [Crenellation], and if the note came down on a second instead of the original note it became [Podium] [G:  g’ b’ a’].  The quilisma ([Upper Mordent]) indicated a repetition of two notes, one above the other, and we still use much the same sign for our trill.  Also the two forms of the circumflex, [Over-slur] [Under-slur], were joined ([Turn]) and thus we have the modern turn, so much used by Wagner.

Now while this notation was ingenious, it still left much to be desired as to pitch.  To remedy this a red line was drawn before writing these signs or neumes, as they were called.  This line represented a given pitch, generally E; above and below it were then written the signs for the notes, their pitch being determined by the relative position they held in regard to the line.  Thus [Podium, Turn, Upper Mordent] was the equivalent of [G:  c’ e’ d’ e’ d’ c’ d’ e’ d’ e’ d’ e’ d’], considering the line as being middle C pitch, a fourth higher F. This was the condition of musical notation in 1000 A.D.

To Guido d’Arezzo is ascribed its development up to some semblance of our present system, although the claim has often been denied.  It is certain, however, that the innovations were made at this period.  In the first place Guido made the red line always stand for the pitch of F, and at a little distance above it he added another line, this time yellow, which was to indicate the pitch of C. Thus the signs began to take very definite meaning as regards pitch; for, given a sign extending from one line to the other, the reader could see at a glance that the music progressed a fifth, from F to C, or vice-versa.  And now the copyists, seeing the value of these lines in determining the pitch of the different signs, of their own account added two more in black ink, one of which they drew between the F and the C line, and the other above the C line, thus [illustration].  By doing this they accurately decided the pitch of