TREFOIL is a trio of singer-instrumentalists long active in early music, with experience in such ensembles as Concert Royal, Les Arts Florissants, New York's Ensemble for Early Music, Pomerium, Clarion Music Society, Piffaro, My Lord Chamberlain's Consort, and other groups. The trio debuted in New York and Philadelphia early in 2000 with a program of 14th century French ars subtilior song. Trefoil has appeared in concerts and master classes at The Cloisters, Temple University, Vassar College, Middlebury College, Vermont Millennium Arts Festival, Museum Series of Providence, Boston College, Currier Museum of Art in Manchester, NH, Neighborhood Music School in New Haven, 2002 Amherst Early Music Festival, and 37th Annual International Congress on Medieval Studies at Kalamazoo. The trio has also made a series of joint appearances with the Folger Concert in Washington D.C.

The complex polyphony of late 14th-century France was performed by small groups of professional minstrels. Each court had its musician-clerks, usually a trio of singers, who were well-versed in the current musical trends and techniques. Some of these clerks were composers, and others may have also been instrumentalists who used vocal music as the basis of a new style of florid counterpoint. In the last quarter of the century, a rhythmically complex style known today as the ars subtilior required these clerks to be fluent in an intricate system of musical notation that included a wide variety of numerical formulae, different uses of colored ink, and a number of exotic note shapes. In preparing this program, we chose to work from medieval notation. This required a slightly longer learning process, sometimes including a bit of trial and error. Only very occasionally did we resort to consulting transcriptions in modern notation and in full score. Working from parts, we were compelled to rely solely on our ears to keep track of one another's part, and found that the rhythmic language was clarified by the economy of the medieval notation.

Fourteenth-century poets made frequent references to figures from their literary past for their writings about love, praise, and war. This practice was inherited from the troubadours’ use of a senhal, or literary pseudonym, that replaced the name of a noble lady, a rival troubadour, or some other person indicated in a poem. Colorful bestiaries – collections of pictures and descriptions of exotic monsters and magical animals – were quite common in late medieval libraries. The troubadours and trouvères often used these animals as symbols of themselves or their love-object in their poems, beginning with a comparison such as "ausi conme unicorne suy" (I am like the unicorn). These creatures were chosen for their symbolic associations. For instance, the unicorn appears as a not-so-subtle metaphor for male desire in Ausi conme Unicorne suy. The basilisk, a serpent with a deadly gaze, appears in a quirky song by Solage; the poet compares its venom to the mortal pain of desire and envy that afflicts all lovers, while its awkward physical nature (see the CD cover) is mirrored in the unusual rhythms and syncopations of the music. In Ung Lion Say a benevolent ruler is compared to a noble beast who is incapable of using his great power against those who possess a pure heart; its notation is such that only the love of its solution will eventually yield a satisfactory musical experience. Perhaps the Lion’s precious stones are mirrored by the special notational symbols, or figures, that adorn the manuscript.

The invocation of mythological figures may serve a more general symbolic function, useful for constructing extended metaphors for the author’s situation. In Se Dedalus, the poet invokes the famous inventor and other classical figures including Zephirus, the god of the west wind, the legendary musician Orpheus, and Jupiter, king of the gods; the poet begs them all to use their special powers to release him from his love-sickness, but to no avail. So many masters and mistresses are named in Se Zephirus/Se Jupiter that the object of the poet's charms would be a downright villainess if she refused him a glance. A different kind of master, Pythagoras, leads a list of those who represent the ancient art of music in Pictagoras. In this ballade, the meaning of the text is mirrored by Pythagorean numerical proportions within the music.

Some musical symbols are easier to see than to hear. For instance, En la maison Dedalus is inscribed within a circular labyrinth that symbolizes one of Dedalus’s ill-fated inventions: the Minotaur’s prison. The singer must double back once before completing the entire circuit. Meanwhile, the two accompanists are in canon; the second player chases the first through the maze, and never completes the entire circle. Much like the narrator, he loses himself in pursuit of an ideal. An even more complex labyrinth is formed by the notation of Tout par compas. Within this circular maze, the musicians performing the canonic melody encounter the mathematical equivalent of dangerous foes to be conquered. By successfully negotiating these mathematical problems, the musicians can continue their way through the maze. To this duo, a third voice provides a continuous accompaniment. La harpe de melodie is famously notated upon the strings of a harp, in which, as in Tout par compas, two of the three performers embark on a hunt (chasse) for each other through a musical maze whose notation is nothing short of a medieval cryptogram. In learning these pieces, musicians traverse a labyrinth of sound, much as a pilgrim would follow the path of the Chartres cathedral labyrinth, making false turns, retracing their steps, and eventually finding the end of the path – the knowledge of a new piece of music, and the delight of the performance.

This music was meant to be sung for living masters, or great lords, who enjoyed hearing themselves and their courts compared to heroes and kingdoms of the distant past. The setting of Le Mont Aon is a legendary mountain-top in ancient Thrace, where nine muses of antiquity are led by Phoebus Apollo. "Febus" was a sehhal for the colorful Count Gaston III of Foix, who ruled a rugged, mountainous kingdom in the south of modern France; his mane of red hair and love of classical allusion inspired a number of courtly lyrics at the end of the 14th century. Both Se Galaas and Se July Cesar contain his famous battle cry: "Febus avant!" (Febus forward!). Egidus' ballade Phiton beste tres venimeuse, based loosely on the earlier ballade by Machaut, begins with the premise that Gaston Febus will conquer a mythical serpent (representative of a local rival kingdom) through his great prowess in war. In these poems, Febus is compared to Arthur, Galahad and Julius Caesar, among other great heroes of ancient battles. These heroes are drawn from a medieval poem in praise of the "nine worthies" – three heroes each drawn from the Bible, the ancient world, and the age of chivalry.

These songs, written in fixed forms containing two or three repeating sections of music, ars subtilior songs invite contemplation in the same way a labyrinth or puzzle would. By shifting the attention among varied musical impulses, the songs continually promise a sense of arrival and just as often delay it. Unlocking the thought-process that created them requires no less patience of the auditors than of the musicians themselves. The seeker who dutifully follows Ariadne's thread to the daylight at the maze's end will emerge having glimpsed the beauty of the late medieval mind.