RESPONSORY. - In the Mass, after the reading, and in the Office at the end of each lesson and in the Little Hours after the Chapter, the soloist sings or recites a verse of a psalm or a passage from Holy Scripture, to which the choir responds.
The first and second are called the prolixum responsory, the rest the breve responsory. Its origin lies in the need to allow the readers to rest between one passage and another and also to give a little variety to the liturgical function. The responsory is indicated by the letter R and is divided by an asterisk into two or three sections, one of which is called the Repetuando, and by a versus, sometimes even more than one, with the final doxology of the Gloria Patri in the last responsory of each Nocturn and in every short responsory, except in Passiontide. In the Office of the Dead the Requiem is used in its place.
The manner in which the responsorial psalmody was sung in the first centuries, when it was introduced, is not known. It may be supposed, on the basis of an allusion by St. Augustine, that the soloist's verses and the choir's response were performed on recitatives and melodies much simpler than the singing of our short responsories and of the present invitatories. Later almost all the melodies would become more ornate and the number of verses consequently reduced, so that it is very rare to find in medieval codices a responsory of more than one verse. In current usage this last form is found only in the responsories Aspiciens a longe and Libera.
Among the different musical forms deriving from the ancient responsorial psalmody, only three have retained the name of responsory. One takes place in the first part of the Mass; it is the gradual responsory, whose structure has been altered by the suppression of the refrain after the verse. The melody of the verse is highly developed: built almost always on a higher scale than that of the first part of the responsory, it offered the soloist the opportunity to perform his part with great virtuosity. The gradual responsories were composed or centonized by preference in the mode of fa, which deserves particular attention inasmuch as this mode was the one exploited in all the other genres of Gregorian music.
The other two forms of responsory are encountered in the Office: the short responsories, performed on very simple melodies, and the long ones, which are often also composed of formulae, but of a more varied and more ornate style. The latter, unlike the gradual responsories, have stereotyped verses comprising two parts with intonation, tenor and cadence; they are fixed in eight melodic schemes corresponding to the eight psalm tones. This regularity later appeared tiresome, and composers modified this rule with exceptions that became ever less rare. From the 10th century onward the responsories, written for the most part in the mode of re, each give a proper verse. Another element of variety comes from a long melisma which, in the most celebrated responsories of the Middle Ages, adorns one of the last words and gives rise to a brief prose. Thus, for example, Inviolata and Sospitati were added to the responsories Gaude Maria Virgo and Ex eius tumba (d.i.s. Nicola). The systematic search for assonances in a in Inviolata, and in o in Sospitati, is a law of the genre: the intention was to prolong as much as possible the timbre of the vowel on which the original melisma rose.
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Eugenio Cardine