It is often the case throughout history that musical innovation begins in a single genre then spreads to others. This is the case in the Renaissance with the motet. For understandable reasons, composers were more willing to try out newer compositional styles in the genre of the motet than they were in the mass. For example, the older cantus firmus technique that arose in the Middle Ages was used in masses for much longer than in motets. In motets, composers moved away from the cantus firms and favored freer, more expressive techniques (including imitative and homophonic textures) far earlier than in the mass. Over time these newer styles eventually spread to other genres including the mass.

In classical music, a motet is a highly varied choral musical composition. The motet was one of the pre-eminent polyphonic forms of Renaissance music.

According to Margaret Bent, “a piece of music in several parts with words” is as precise a definition of the motet as will serve from the 13th to the late 16th century and beyond. This is close to one of the earliest descriptions we have, that of the late 13th-century theorist Johannes de Grocheo, who believed that the motet was “not to be celebrated in the presence of common people, because they do not notice its subtlety, nor are they delighted in hearing it, but in the presence of the educated and of those who are seeking out subtleties in the arts.”

Etymology

In the early twentieth century, it was generally believed the name came from the Latin movere, (“to move”), though a derivation from the French mot (“word” or “phrase”), had also been suggested. The Medieval Latin for “motet” is motectum, and the Italian mottetto was also used. If the word is from Latin, the name describes the movement of the different voices against one another. Today, however, the French etymology is favoured by reference books, as the word “motet” in thirteenth-century French had the sense of “little word.”

Medieval Motets

The earliest motets arose in the thirteenth century from the organum tradition exemplified in the Notre Dame school of Léonin and Pérotin. The motet probably arose from the addition of text to the long melismatic passages of organum. The motet took a definite rhythm from the words of the verse, and as such appeared as a brief rhythmic interlude in the middle of the longer, more chantlike organum.

The practice of discant over a cantus firmus marked the beginnings of counterpoint in Western music. From these first motets arose a medieval tradition of secular motets. These were two or three part compositions in which several different texts, sometimes in different vernacular languages, were sung simultaneously over a Latin cantus firmus that once again was usually adapted from a passage of Gregorian chant. It is suspected that, for the sake of intelligibility, in performance the cantus firmus and one or another of the vocal lines were performed on instruments. Among the trouvères, Robert de Reins La Chievre and Richart de Fournival composed motets.

Renaissance Motets

The motet was preserved in the transition from medieval to Renaissance music, but the character of the composition was entirely changed. While it grew out of the medieval motet, the Renaissance composers of the motet generally abandoned the use of a repeated figure as a cantus firmus. Instead, the Renaissance motet is a polyphonic musical setting, sometimes in imitative counterpoint, for chorus, of a Latin text, usually sacred, not specifically connected to the liturgy of a given day, and therefore suitable for use in any service. The texts of antiphons were frequently used as motet texts. This is the sort of composition that is most familiarly designated by the term “motet,” and the Renaissance period marked the flowering of the form.

In essence, these motets were sacred madrigals. The relationship between the two forms is most obvious in the composers who concentrated on sacred music, especially Giovanni Pierluigi da Palestrina, whose “motets” setting texts from the Canticum Canticorum, the biblical “Song of Solomon,” are among the most lush and madrigal-like of Palestrina’s compositions, while his “madrigals” that set poems of Petrarch in praise of the Blessed Virgin Mary would not be out of place in church. The language of the text was the decisive feature: if it’s Latin, it’s a motet; if the vernacular, a madrigal. Religious compositions in vernacular languages were often called madrigali spirituali, “spiritual madrigals.”

In the latter part of the sixteenth century, Giovanni Gabrieli and other composers developed a new style, the polychoral motet, in which two or more choirs of singers (or instruments) alternated. This style of motet was sometimes called the Venetian motet to distinguish it from the Netherlands or Flemish motet written elsewhere.

https://courses.lumenlearning.com/vccs-tcc-mus121-1/chapter/motet-e/