Why is the ninth month called September?
in musical notation, a sign for one or a group of successive musical pitches, predecessor of modern musical notes. Neumes have been used in Christian (e.g., Gregorian, Byzantine) liturgical chant as well as in the earliest medieval polyphony (music in several voices, or parts) and some secular monophony (music consisting of a single melodic line). Early neumes developed from Greek textual accents that were gradually modified into shapes showing pitch direction and vocal ornament. These staffless, or chironomic, neumes facilitated recall of a memorized melody in accordance with the semi-oral musical practices of the time. Before long, neumes were "heighted" so as to suggest specific melodic lines. A musical staff of four lines evolved about the year 1000. Neumes placed on the staff showed exact pitch, allowing a singer to read an unfamiliar melody. Even within western Europe, differing systems of neumes were used in different geographical regions. By about 1200, neumes had assumed the characteristic square shapes still used in the modern notation of Gregorian chant. Whether and how neumes indicated rhythm remains a subject of controversy. Musical notes with time values evolved from neumes in the last half of the 13th century.