Music and text
Isaac's musical settings in Choralis Constantinus II exhibit many compositional techniques inspired by the meaning of the words. These techniques are most common in sequences, which often have words that lend themselves to musical interpretations.
It would not be practical to enumerate all such instances here. The following lists provide characteristic examples of each type of technique.
The most common techniques for interpreting the texts musically are those that call attention to important words through contrast with the surrounding music. Other techniques include extensive repetition of a word or group of words, numerical symbols, notational symbols, and affective or pictorial symbols.
Long notes and homorhythm
Important words and names are often set off with long notes in homorhythmic texture, usually preceded and sometimes followed by rests. Long notes and homorhythmic textures may also be used independently for less striking emphasis.
- Introit 20: "Iesu Christi"
- Alleluia 1 (verse): "lux" ("light")
- Alleluia 3 (verse): "adorare Dominum" ("to worship the Lord")
- Sequence 3, v. 12: "paenitet me fecisse hominem" ("I regret having made man") - a quotation of the words of God
- Sequence 14, v. 12: "o Patris sapientia" ("o wisdom of the Father")
- Sequence 17, v. 18: "martyr Christi" ("martyr of Christ")
- Sequence 24, v. 6: "constantia" ("constancy") - a pun on the name of St. Conrad and the city for which the piece was composed
- Sequence 24, v. 10: "Udalrici"
- Communion 13: "Elisabet"
New voice entry
The entry of a voice that has not been heard previously, or that has been resting for a significant amount of time, may highlight the words at the point of entry. In some cases this technique represents the appearance of a new phenomenon.
- Tract 4, v. 3: "et post partum virgo inviolata permansisti" ("and after the birth you remained an inviolate virgin")
- Tract 5, v. 6: This verse increases systematically from two voices to three, then four, to lead to the climactic words "filius Dei" ("son of God") in the concluding section.
- Sequence 1, v. 6: The words "vetustas mundi depulerit genitus tenebras" ("driven away the ancient darkness of the world") are set off by a re-entry of the top voice, representing the new state of light in the world.
- Sequence 9, v. 6: The top voice enters for the first time at the words "vetustatem novitas . . ." ("the new puts the old [to flight]"), again representing a new state with a new voice.
- Sequence 23, v. 14: The top voice enters for the first time at the words "virgo voto statuit," ("she determined by vow to remain a virgin"), emphasizing the crucial words of the verse.
All of the verses set for five or six voices are of special importance. When expanded textures are used in one or more verses of a sequence, the last verse is normally included, but in Sequence 20, only the penultimate verse has an extra voice, because it is the one in which the words speak of triumph.
Striking melodic and rhythmic motives
Isaac sometimes uses striking melodic or rhythmic motives to call attention to particular words. In some cases, the pitches of these motives are derived from the cantus firmus, but Isaac sets them in ways that make them grab the listeners' attention.
- Introit 14: The litany text (a second cantus firmus) is set to unusually fast declamation on repeated semiminims, intensifying the urgency of the prayer, "Sancta Maria Magdalena, ora pro nobis" ("St. Mary Magdalen, pray for us").
- Introit 18: The words of the second cantus firmus Cum iocunditate are likewise set off with declamation on repeated semiminims.
- Sequence 2, v. 4: The words "semper rutilans, semper clara" ("always shining, always bright") are set to a fast, stepwise ascent of a twelfth, followed by leaps of fifths and octaves, in the bass.
- Sequence 3, v. 12: The word "oblita" ("forgotten") is set to a falling fifth in semibreves surrounded by rests and imitated in all voices.
- Sequence 14, v. 6: The name "Mariam Magdalenam" is set to a descending scale in the altus and bass, contrasting with long notes in the other voices
- Sequence 14, v. 22: The words "nos salva" ("save us") are set to a descending fourth in semibreves, imitated in four of the five voices.
- Sequence 22, v. 14: The words "coelesti lumine" ("with heavenly light") are underscored by a series of repeated-note minims in the bass and altus.
Repetition of individual words or short groups of words separated by rests is a common means of emphasis. It is sometimes extended to the point that these words and their associated musical motives form the basis of entire sections of pieces.
- Sequence 2, v. 10: "haec praedicta" ("these things were foretold")
- Sequence 3, v. 6: "quem sidus praedicat" ("which the star announces")
- Communion 5: "Emmanuel"
- Sequence 9, v. 20: "cum Isaac immolatur" ("he is sacrificed with Isaac") - possibly highlighted because of the identity of the composer's name with the biblical figure in the text
- Sequence 10, v. 14: "Angelis" ("of the Angels")
- Sequence 14, v. 20: "qualis sit tu scis" ("what sort of woman she is you know")
- Sequence 20, v. 18: "reprimit" ("subdues"), before "daemonia" ("devils")
References to numbers in the texts often elicit a musical response in which some aspect of the music corresponds to the number.
- Introit 11: The word "unum" appears in only one voice, though another voice accompanies it with a different word, since a reduction of the texture to a single voice would be out of character with the musical style.
- Alleluia 11 (verse): The first two phrases, which describe the two saints as "duae olivae" ("two olive trees") and "duo candelabra" ("two candlesticks") are set to opposite pairs of voices (D/A, then T/B).
- Communion 8: The word "omnes" ("all") coincides with an expansion of the texture from three voices to four.
- Sequence 19, v. 24: The words "atque triplex hierarchia" (and the triple hierarchy) are imitated by three voices on a striking triadic motive (from the cantus firmus) in semibreves. The other two voices accompany them with different words, then state "atque triplex hierarchia" in triplets (sesquialtera rhythms) signed 3.
Two verses use major (= perfect) prolation to represent the word "maior".
- Sequence 9, v. 2: The verse is a mensuration canon between perfect tempus and major prolation, probably inspired by the word "maior" in the text.
- Sequence 13, v. 2: Major prolation appears only on the word "maior" itself in the upper three voices. The bass begins in major prolation, but has only rests before the key word enters. After that word all voices switch to C followed by minim sesquialtera.
Affective and pictorial symbols
Affective and pictorial symbols are more difficult to judge than the preceding types of musical interpretations of words, but some are unambiguous. Where they occur, they contribute significantly to the expressive character of the music.
- Alleluia 8 (verse): The word "amoris" is preceded by a rest in the discant and set to a skip to the highest note in the verse; that note is held for a dotted semibreve and followed by a slow, stepwise descent to a phrygian cadence. The effect, though subtle, is deeply expressive.
- Sequence 2, v. 4: The monotone on a high pitch in the altus throughout the verse suggests the idea of the constancy of a sun that never sets and a star that never stops shining.
- Sequence 2, v. 8: The words "passum est" ("suffered") are set in fauxbourdon in the lower voices and end with a phrygian cadence.
- Sequence 6, v. 10: The word "mortuos" ("dead") is set off by rests and set to repeated notes in a sinister, syncopated rhythm.
- Sequence 6, v. 22: The word "resurgens" ("arising") is set to fast, ascending scales that rise an octave in the tenor and a seventh in the altus.
- Sequence 7, v. 12: The word "praepeti" ("fast-flying") has the unusually quick rhythm of a texted dotted minim-semiminim in all voices. It is repeated after a breathless two-minim phrase end in the discant. The final cadence of the verse on the following word, "transvolans" ("flying past"), ends with a third over the bass in the alto that rises to a fifth through the same dotted rhythm.
- Sequence 8, v. 18: The idea of chaos and disunity resulting from the many languages spoken by the builders of the Tower of Babel is represented by an off-kilter rhythm in the cantus firmus (alternating perfect and imperfect breves) and dense imitation of fast motives in the other voices. The only internal cadence in the verse appears (briefly) on the word "adunasti," but the chaotic texture continues beyond it. This is the only verse in all of Choralis II with a 2-flat signature.
- Sequence 12, v. 8: The words "doctilogos philosophos" ("learned philosophers") are set to slow dotted rhythms that sound distinctly pompous when they appear in augmentation in the bass.
- Sequence 13, v. 4: The words "clamat intra" ("proclaims within") are set to incisive repeated notes at the top of the register in the altus, like the voice of a town cryer.
- Seqiemce 20, v. 6: The words "haec est scala" ("this is the ladder") begin with a striking scale that rises a ninth in the altus, followed by a shorter scale on the word "scala" itself in the discant.
- Communion 19: The word "pulsanti" ("knocking") is set to repeated notes in the altus and bass in a rhythm that suggests the sound of knockng.