The communion time provides perhaps the greatest opportunity in the Mass to employ additional music. In most parishes, communicants are numerous, and providing music for the whole time may even be a challenge. The communion antiphon alternated with psalm verses is one good solution--it is expandable to suit the time, according to the number of verses and repetitions of the antiphon. The publication Communio by the Church Music Association of America provides those antiphons with their verses. There may also be time for some playing of the organ or a hymn sung by the congregation. If the choir is capable of it, however, a motet can be a very suitable conclusion to the communion time. It should be on a text appropriate to the season, or on a generally appropriate liturgical text, such as, for instance, Sicut cervus desiderat ad fontes aquarum, or even better, on a traditional Eucharistic text.
We have from the Renaissance a number of such Eucharistic motets; one in particular, has been a favorite of the congregation for which my choir sings: Pierre de La Rue's O salutaris hostia. This motet is found within the Sanctus of La Rue's Missa de Sancta Anna, where it replaces the first Osanna. It is thus an "elevation" motet, a devotional piece meant to be sung at the elevations of the the host and the chalice. It must be remembered that until the Second Vatican Council, the Sanctus was sung during the silent recitation of the Canon of the Mass, and that the first Osanna is a likely place for the elevation to take place. Such elevation motets within Sanctus movements are also found in works of Josquin Des Prez, in a complete Mass (Tu solus qui facis mirabilia in the Missa D'ung aultre amer), and in two independent Sanctus movements (Tu lumen, tu splendor Patris in Sanctus D'ung aultre amer and Honor et benedictio in Sanctus de passione).
Joseph Jungmann cites examples from the thirteenth century and later of prayers of devotion provided to the laity for recitation at the elevation of the Blessed Sacrament, and also of later sung pieces for the elevation: By 1450, O sacrum convivium was sung in Strassburg after the Benedictus; in 1512, King Louis XII of France ordered O salutaris hostia to be sung at Notre Dame Cathedral between the Sanctus and Benedictus; by 1521 Ave verum corpus and Gaudete flores were also sung at Paris. (1)
A particularly notable use of such motets is found in the unusual practice at Milan known as motetti missales--motets on various sacred texts that replaced the proper liturgical texts; thus a motet designated "loco sanctus" would be sung while the priest recited the normative text of the Sanctus. These motetti missales included elevation motets, often designated "ad elevationem," and on such texts as O salutaris hostia and Adoramus te, Christe. They were in a very homophonic style, often marked with fermatas, sometimes concluding with a section in quick triple time. Stylistically this homophonic style has origins in the lauda, a devotional piece, sometimes in Italian, sung by lay brotherhoods called laudesi. The laude were very simple part songs in a consistently homophonic style.
Elevations survived into the nineteenth and twentieth centuries, witness Caesar Frank's Mass in A, Op. 12, which originally included an O salutaris hostia after the Benedictus; this was later replaced with the well-known Panis angelicus. Likewise, Pie Jesu Domine is found as an elevation in such Requiem Masses as those of Luigi Cherubini, Gabriel Faure, and Maurice Durufle. The Cistercian order maintained elevations in chant until the time of the Second Vatican Council: normally O salutaris hostia, but for Masses of the Blessed Virgin, Ave verum Corpus, and for Requiem Masses, Pie Jesu Domine, "Pie Jesu Domine, dona eis requiem," three times, with the addition of "sempiternam" the third time. The motu proprio of St. Pius X provided only one place for a motet in the solemn Mass--after the Benedictus--evidently an elevation motet. …