The ''Micrologus'' is a treatise on

Medieval music Medieval music encompasses the sacred and secular music of Western Europe during the Middle Ages, from approximately the 6th to 15th centuries. It is the first and longest major era of Western classical music and followed by the Renaissance ...

written by

Guido of Arezzo Guido of Arezzo ( it, Guido d'Arezzo; – after 1033) was an Italian music theorist and pedagogue of High medieval music. A Benedictine monk, he is regarded as the inventor—or by some, developer—of the modern staff notation that had a ma ...

, dating to approximately 1026. It was dedicated to

Tedald, Bishop of Arezzo Tedald (c. 990 – 12 June 1036), also known as Theodald, Theodaldus, Tedaldus, Tedaldo, or Teodaldo, was the forty-third Bishop of Arezzo from 1023 until his death. Tedald came from the highest ranks of the nobility of central Italy. He was ...

. This treatise outlines singing and teaching practice for

Gregorian chant Gregorian chant is the central tradition of Western plainchant, a form of monophonic, unaccompanied sacred song in Latin (and occasionally Greek) of the Roman Catholic Church. Gregorian chant developed mainly in western and central Europe durin ...

, and has considerable discussion of the composition of polyphonic music. This treatise discusses modified parallel

organum ''Organum'' () is, in general, a plainchant melody with at least one added voice to enhance the harmony, developed in the Middle Ages. Depending on the mode and form of the chant, a supporting bass line (or '' bourdon'') may be sung on the same ...

as well as free organum. The examples given are in two voices, set note-against-note, and the voices are frequently permitted to

cross A cross is a geometrical figure consisting of two intersecting lines or bars, usually perpendicular to each other. The lines usually run vertically and horizontally. A cross of oblique lines, in the shape of the Latin letter X, is termed a sa ...

. He advised against use of the

perfect fifth In music theory, a perfect fifth is the Interval (music), musical interval corresponding to a pair of pitch (music), pitches with a frequency ratio of 3:2, or very nearly so. In classical music from Western culture, a fifth is the interval fro ...

and

minor second A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically. It is defined as the interval between two adjacent no ...

, favouring instead the

major second In Western music theory, a major second (sometimes also called whole tone or a whole step) is a second spanning two semitones (). A second is a musical interval encompassing two adjacent staff positions (see Interval number for more deta ...

and

perfect fourth A fourth is a musical interval encompassing four staff positions in the music notation of Western culture, and a perfect fourth () is the fourth spanning five semitones (half steps, or half tones). For example, the ascending interval from C to ...

(though thirds were also permitted). One point of importance is his guideline for the occursus (meaning "meeting" or "concurrence", running on the same path), which is a predecessor of the later

cadence In Western musical theory, a cadence (Latin ''cadentia'', "a falling") is the end of a phrase in which the melody or harmony creates a sense of full or partial resolution, especially in music of the 16th century onwards.Don Michael Randel (1999) ...

. An occursus occurs where two voices approach a

unison In music, unison is two or more musical parts that sound either the same pitch or pitches separated by intervals of one or more octaves, usually at the same time. ''Rhythmic unison'' is another term for homorhythm. Definition Unison or per ...

. He suggested that the unison should be approached either by contrary motion from a

major third In classical music, a third is a musical interval encompassing three staff positions (see Interval number for more details), and the major third () is a third spanning four semitones. Forte, Allen (1979). ''Tonal Harmony in Concept and P ...

, or

oblique motion In music theory, contrapuntal motion is the general movement of two melodic lines with respect to each other. In traditional four-part harmony, it is important that lines maintain their independence, an effect which can be achieved by the judicio ...

from a

.Hoppin, Richard H. ''Medieval Music''. Norton, 1978, pp. 194-195.

References

External links

Micrologus Guidonis de disciplina artis musicae
Medieval music manuscript sources {{Medieval-music-theory-stub