musical notation, symbols used to make a written record of
musical sounds. Two different systems of letters were used to
write down the instrumental and the vocal music of ancient
Greece. In his five textbooks on music theory Boethius (c.A.D.
470–A.D. 525) applied the first 15 letters of the alphabet to
the notes in use at the end of the Roman period. Notation of
Gregorian chant was by means of neumes, which are thought to
have been derived from symbols used in the Greek language to
indicate pitch inflection. Neumes were certainly in use by the
6th cent., although the earliest extant manuscripts containing
them are fragmentary ones from the 8th cent. These neumes
indicated only the grouping of sounds in a given melody,
evidently to recall to a singer the approximate shape of a
melody already learned by ear. Heighted neumes, arranged above
and below a line, made the intervals of a melody more
discernible in 10th-century notation, and by the end of the 12th
cent. the staff perfected by Guido d'Arezzo was in use