(from Gk enchiridion, “handbook”), title of a treatise probably written by abbot Hoger around 900 at Werden abbey near Essen, the first to discuss polyphonic music (organum). It divides the whole range of notes into 4½ tetrachords (four-note series) with a semitone in the middle of each. It uses the so-called dasia signs for song notation, derived from a basic sign similar to F (Notation, musical). Most sources continue the treatise with the Scolica enchiriadis de musica.
Source: Musica et Scolica enchiriadis, ed. H. Schmid, 1981