The different parts of the Roman communion office are not all of the same antiquity. Its essential and characteristic features are most easily caught, and their rationale best understood, by reference to the earliest Sacramentaries (particularly the Gregorian, which was avowedly the basis of the labours of the Tridentine committee), to the Gregorian Antiphonary, and to the oldest redaction of the Ordo Romanus. The account of the mass (qualiter Missa Romana celebratur) as given by the Sacramentarium Gregorianum is to the effect that there is in the first place “the Introit according to the time, whether for a festival or for a common day; thereafter Kyrie Eleison. (In addition to this Gloria in Excelsis Deo is said if a bishop be [the celebrant], though only on Sundays and festivals; but a priest is by no means to say it, except only at Eastertide. When there is a litany (quando letania agitur) neither Gloria in Excelsis nor Alleluia is sung.) Afterwards the Oratio is said, whereupon follows the Apostolus, also the Gradual and Adleluia. Afterwards the Gospel is read. Then comes the Offertorium, and the Oratio super oblata is said.” Then follow the Sursum Corda, the Preface, Canon, Lord’s Prayer and “embolism” (Ιρβόλισρα. or insertion, Libera nos, Domine), given at full length precisely as they still occur in the Roman missal.

In every liturgy of all the five groups a passage similar to this occurs, beginning with Sursum Corda, followed by a Preface and the recitation of the Sanctus or Angelic Hymn. The “canon” or consecration prayer, which in all of them comes immediately after, invariably contains our Lord’s words of institution, and (except in the Nestorian liturgy) concludes with the Lord’s Prayer and “embolism.” But within this framework there are certain differences of arrangement, furnishing marks by which the various groups of liturgies can be classified (see vol. xiv. p. 709 sq.). Thus it is distinctive of the liturgy of Jerusalem that the “great intercession” for the quick and the dead follows the words of institution and an Epiklesis (lπiκλησus τoυ πveυμaτoς αγίου) OΓ petition for the descent of the Holy Spirit upon the gifts; in the Alexandrian the “great intercession” has its place in the Preface ; in the East Syrian it comes between the words of restitution and the Epiklesis; in the Ephesine it comes before the Preface; while in the Roman it is divided into two, the commemoration of the living being before, and that of the dead after, the words of institution. Other distinctive features of the Roman liturgy are (1) the position of the “Pax” after the consecration, and not as in all the other liturgies at a very early stage of the service, before the Preface even; and (2) the absence of the Epiklesis common to all the others.

The words of its “canonical prayer” are of unknown antiquity; they are found in the extant manuscripts of the Sacramentarium Gelasianum, and were already old and of forgotten authorship in the time of Gregory the Great, who, in a letter to John, bishop of Syracuse {Registr. Epist., vii. 64), speaks of it as “the prayer composed by a ‘scholastic’” (precem quam scholasticus composuerat). The same letter is interesting as containing Gregory’s defence, on the ground of ancient use, of certain parts of the Roman ritual to which the bishop of Syracuse had taken exception as merely borrowed from Constantinople. Thus we learn that, while at Constantinople the Kyrie Eleison was said by all simultaneously, it was the Roman custom for the clergy to repeat the words first and for the people to respond, Christe Eleison being also repeated an equal number of times. Again, the Lord’s Prayer was said immediately after the consecration aloud by all the people among the Greeks, but at Rome by the priest alone.

The somewhat meagre and imperfect liturgical details furnished by the Sacramentarium Gregorianum are supplemented in a very full and interesting manner by the successive texts of the Ordo Romanus, the first of which dates from about the year 730. The ritual they enjoin is that for a pontifical high mass in Rome itself; but the differences to be observed by a priest “quando in statione facit missas” are comparatively slight. Subjoined is a précis of 0rdo Romanus I.

It is first of all explained, that Rome has seven ecclesiastical regions, each with its proper deacons, subdeacons, and acolytes. Each region has its own day of the week for high ecclesiastical functions, which are celebrated by each in rotation. [This accounts for the Statio ad S. Mariam Majorem, ad S. Crucem in Jerusalem, ad S. Petrum, &c., prefixed to most of the masses in the Gregorian Sacramentary , and still retained in the “Proprium de Tempore” of the Roman missal.] The regulations for the assembling and marshalling of the procession by which the pontiff is met and then escorted to the appointed station are minutely given, as well as for the adjustment of his vestments “ut bene sedeant,” when the sacristy has been reached. He does not leave the sacristy until the Introit has been begun by the choir in the church. Before the Gloria he takes his stand at the altar, and after the Kyrie Eleison has been sung (the number of times is left to his discretion) he begins the Gloria in Excelsis, which is taken up by the choir. During the singing he faces eastward; at its close he turns round for a moment to say “Pax vobis,” and forthwith proceeds to the Oratio This finished, all seat themselves in order while the subdeacon ascends the ambo and reads [the Epistle}. After he has done, the cantor with his book (cantatorio) ascends and gives out the response {Responsum} with the Alleluia and Tractus in addition if the season calls for either. The deacon then silently kisses the feet of the pontiff and receives his blessing in the words “Dominus sit in corde tuo et in labiis tuis.” Preceded by acolytes with lighted candles and subdeacons burning incense, he ascends the ambo, where he reads the Gospel. At the close, with the words “Pax tibi” and “Dominus vobiscum,” the pontiff, after another Oratio, descends to the “senatorium” accompanied by certain of the inferior clergy, and receives in order the oblations of the rulers (oblationes principum), the archdeacon who follows taking their “amulas” of wine and pouring them into a larger vessel; similar offerings are received from the other ranks and classes present, including the women. This concluded, the pontiff and archdeacon wash their, hands, the offerings being meanwhile arranged by the subdeacons on the altar, and water, supplied by the leader of the choir (archiparaphonista), being mingled with the wine. During this ceremony the schola have been engaged in singing the Offertorium·, when all is ready the Sontiff signs to them to stop, and enters upon the Preface, the sub-eacons giving the responses. At the Angelic Hymn {Sanctus} all kneel and continue kneeling, except the pontiff, who rises alone and begins the Canon. At the words “per quem haec omnia” the archdeacon lifts the cup with the oblates, ana at ' ‘ Pax Domini sit semper vobiscum” he gives the peace to the clergy in their order, and to the laity. The pontiff then breaks off a particle from the consecrated bread and lays it upon the altar; the rest he places on the paten held by the deacon. It is then distributed while Agnus Dei is sung. The pontiff in communicating puts the particle into the cup, saying, “Fiat commixtio et consecratio corporis et sanguinis Domini nostri Jesu Christi accipientibus nobis in vitam aeternam.” Those present communicate in their order under this species also.

As the pontiff descends into the senatorium to give the communion, the schola begins the communion Antiphon, and continues singing the Psalm until, all the people having communicated, they receive the sign to begin the Gloria, after which, the verse having been again repeated, they stop. The celebrant, then, facing eastward, offers the Oratio ad Complendum, which being finished the archdeacon says to the people, “Ite, missa est,” they responding with “Deo gratias.”

To complete our idea of the Roman communion office as it was prior to the end of the 8th century we must now turn to the Gregorian Antiphonariτιs sive Gradualis Liber ordinatus per circulum anni, which as its name implies contains those variable portions of the mass which were intended to be sung by the schola or choir. It gives for each day for which a proper mass is provided—(1) the Antiphona (Antiphona ad Introitum) and Psalmus ; (2) the Responsorium and Versus, with its Alleluia and Versus ; (3) the Offertorium and Versus ; (4) the Communio and Psalmus. Some explanation of each of these terms is necessary. (1) The word Antiphon (αντίφωναν, Old English Antefn, English Anthem) in its ecclesiastical use has reference to the very ancient practice of relieving the voices of the singers by dividing the work between alternate choirs. In one of its most usual meanings it has the special signification of a sentence (usually scriptural) constantly sung by one choir between the verses of a psalm or hymn sung by another. According to the Roman liturgiologists it was Pope Celestine who enjoined that the Psalms of David should be sung (in rotation, one presumes) antiphonally before mass; in process of time the antiphon came to be sung at the beginning and end only, and the psalm itself was reduced to a single verse. In the days of Gregory the Great the introit appears to have been sung precisely as at present,—that is to say, after the antiphon (proper and par excellence), the Psalmus with its Gloria, then the antiphon again. (2) The Responsorium, like the Greek antiphon, derives its name from the responsive manner of singing. As introduced between the epistle and gospel it was probably at first a comparatively long passage, usually an entire psalm or canticle, originally given out by the cantor from the steps from which the epistle had been read (hence the later name Graduale), the response being taken up by the whole choir. (3) The Offertorium and Communio correspond to the “hymn from the book of Psalms” mentioned by early authorities (see, for example, Augustine, Retr., ii. 11; Ap. Const., viii. 13) as sung before the oblation and also while that which had been offered was being distributed to the people. A very intimate connexion between these four parts of the choral service can generally be observed; thus, taking the first Sunday in the ecclesiastical year, we find both in the Antiph<mary and in the modern Missal that the antiphon is Ps. XXV. 1-3, the psalmus Ps. xxv. 4, the responsorium (graduale) and versus Ps. xxv. 3 and xxv. 4, the offertorium and versus Ps. xxv. 1-3 and Ps. xxv. 5. The communio is Ps. lxxxv. 12, one of the verses of the responsorium being Ps. lxxxv. 7. In the selection of the introits there are also traces of a certain rotation of the psalms in the Psalter having been observed.

The first pages of the modern Roman missal are occupied with the Calendar and a variety of explanations relating to the year and its parts, and the manner of determining the movable feasts. The general rubrics (Rubricae Generales Missalis) follow, explaining what are the various kinds of mass which may be celebrated, prescribing the hours of celebration, the kind and colour of vestments to be used, and the ritual to be followed (ritus celebrandi missam), and giving directions as to what is to be done in case of various defects or imperfections which may arise. The Praeparatio ad Missam, which comes next, is a short manual of devotion containing psalms, hymns, and prayers to be used as opportunity may occur before and after celebration. Next comes the proper of the season (Proprium Missarum de Tempore), occupying more than half of the entire volume. It contains the proper introit, collect (one or more), epistle, gradual (tract or sequence), gospel, offertory, secreta (one or more), communion, and post-communion for every Sunday of the year, and also for the festivals and ferias connected with the ecclesiastical seasons, as well as the offices peculiar to the ember days, Holy Week, Easter, and Whitsuntide. Between the office for Holy Saturday and that for Easter Sunday the ordinary of the mass (Ordo Missae), with the solemn and proper prefaces for the year, and the canon of the mass are inserted. The proper of the season is followed by the proper of the saints (Proprium Sanctorum), containing what is special to each saint’s day in the order of the calendar, and by the Commune Sanctorum, containing such offices as the common of one martyr and bishop, the common of one martyr not a bishop, the common of many martyrs in paschal time, the common of many martyrs out of paschal time, and the like. A variety of masses to be used at the feast of the dedication of a church, of masses for the dead, and of votive masses (as for the sick, for persons journeying, for bridegroom and bride) follow, and also certain benedictions. Most missals have an appendix also containing certain local masses of saints to be celebrated “ex induito apostolico.”

Masses fall into two great subdivisions :—(1) ordinary or regular (secundum ordinem officii), celebrated according to the regular rotation of fast and feast, vigil and feria, in the calendar; (2) extraordinary or occasional (extra ordinem officii), being either “votive” or “for the dead,” and from the nature of the case having no definite time prescribed for them. Festival masses are either double, half-double, or simple, an ordinary Sunday mass being a half-double. The difference depends on the number of collects and secretae; on a double only one of each is offered, on a halfdouble there are two or three, and on a simple there may be as many as five, or even seven, of each. Any mass may be either high (missa solennis) or low (missa privata). The distinction depends upon the number of officiating clergy, certain differences of practice as to what is pronounced aloud and what inaudibly, the use or absence of incense, certain gestures, and the like. Solitary masses are forbidden; there must be at least an acolyte to give the responses. The vestments prescribed for the priest are the amice, alb, cingulum or girdle, maniple, stole, and chasuble (planeta); see Costume, vol. vi. p. 462. There are certain distinctions of course for a bishop or abbot. The colour of the vestments and of the drapery of the altar varies according to the day, being either white, red, green, violet, or black. This last custom does not go much further back than Innocent III., who explains the symbolism intended.

Subjoined is an account of the manner of celebrating high mass according to the rite at present in force.

1. The priest who is to celebrate, having previously confessed (if necessary) and having finished matins and lauds, is to seek leisure for private prayer (fasting) and to use as he has opportunity the ‘ ‘ prayers before mass” already referred to. How the robing in the sacristy is next to be gone about is minutely prescribed, and prayers are given to be used as each article is put on. The sacramental elements having previously been placed on the altar or on a credence table, the celebrant enters the church and takes his stand before the lowest step of the altar, having the deacon on his right and the subdeacon on his left. After invoking the Trinity (In nomine Patris, &c. ) he repeats alternately with those who are with him the psalm “Judica me, Deus,” which is preceded in the usual way by an antiphon (Introibo ad altare Dei), and followed also by the Gloria and Antiphon. The versicle “Adjutorium nostrum,” with its response “Qui feoit,” is followed by the “Confiteor,” said alternately by the priest and by the attendants, who in turn respond with the prayer for divine forgiveness, “Misereatur.” The priest then gives the absolution (“Indulgentiam ”), and after the versicles and responses beginning “Deus, tu conversus” he audibly says, “Oremus,” and ascending to the altar silently offers two short prayers, one asking for forgiveness and liberty of access through Christ, and another indulgence for himself “through the merits of thy saints whose relics are here.” Receiving the thurible from the deacon he incenses the altar, and is thereafter himself incensed by the deacon. He then reads the Introit, which is also sung by the choir; the “Kyrie Eleison” is then said, after which the words “Gloria in Excelsis” are sung by the celebrant and the rest of the hymn completed by the choir.

2. Kissing the altar, and turning to the people with the formula “Dominus vobiscum,” the celebrant proceeds with the collect or collects proper to the season or day, which are read secretly. The epistle for the day is then read by the subdeacon, and is followed by the gradual, tract, alleluia, or sequence, according to the time. This...