by Michael Davies
The evolution of what we call Low Mass is the most important of the modifications referred to by Father Fortescue. The simplicity of the Low Mass could give rise to the impression that it is the primitive form. Nothing could be further from the truth. It is, in fact, a late abridgment. All that has been written concerning the Roman Mass so far has concerned what we would describe as the High Mass. From the beginning we read of the liturgy being celebrated with deacons and assistants and in the presence of the people who sing their part. Until the Middle Ages, Mass was not said more than once on the same day. The bishop or senior cleric celebrated, and the rest of the clergy either received Communion or concelebrated. This is still the practice in the Eastern Churches, where there is no equivalent to our Low Mass and where the original practice of one altar in each church is still kept. By the early Middle Ages in the West, every priest offered his own Mass each day, a practice which had far-reaching effects, not only upon the liturgy, but upon Church architecture and even Canon Law.
The change came about for theological reasons. Each Mass as a propitiatory sacrifice has a definite value before God; therefore, two Masses are worth twice as much as one. The custom arose of offering each Mass for a definite intention and the acceptance of a stipend for so doing. This was particularly the case where Requiem Masses were concerned. Faithful Catholics would make provision in their wills for Masses to be said for their souls and would make endowments to monastic foundations for this purpose. In the later Middle Ages, chantries were established for the specific purpose of offering requiems for a particular person, and it was the common practice of all medieval guilds to have Masses said for their deceased members. By the 9th century, the multiplication of Masses had progressed so far that many priests said Mass several times a day. [In the 13th century, action would be taken to curb the excessive multiplication of Masses, and a number of synods forbade priests to celebrate more than once a day, except on Sundays and feast days and in cases of necessity.]
The multiplication of Masses led to the building of many altars in the same church and in monasteries where many priests would celebrate at the same time on different altars. By the 9th century every large monastery was called upon to offer hundreds or even thousands of Masses each year. All these factors led to the abridged service that we call Low Mass, and it was Low Mass that caused the compilation of the Missal as we know it today.
In the earlier period, as we have seen, the books were arranged for the specific people who used them. The priest's book was the Sacramentary, containing his part of Mass and other services. He did not need to have the lessons or antiphons in his book, as he did not say them. But at a private celebration he did say these parts himself, substituting for the absent ministers and choir. Books had to be compiled containing these parts too, and the process had begun as early as the 6th century in Sacramentaries which show the beginning of this development. By the 9th century the Common Masses of Saints are often provided with Epistle, Gospel and choir's part. The 10th century saw the first attempts to compile what is known as the Perfect Missal, Missale plenarium, giving the text of the whole Mass.
The necessity for a truly comprehensive Perfect Missal was given a particular stimulus by the need in Rome under the pontificate of Pope Innocent III for a book that could be used by the members of the Roman curia, who had come to travel widely and frequently in undertaking their duties. It was compiled under the name of Missale Secundum Consuetudinem Romanae Curiae, and it spread everywhere with the final triumph of the Roman Rite. This was caused to no small extent by its adoption by the newly founded Franciscan friars, who carried it with them everywhere during their rapid spread, and, of course, eventually to the New World. From the 13th century onwards one hears no more of Sacramentaries.
Low Mass then reacted on High Mass. Originally the celebrant said or sang his part and listened, like everyone else, to the other parts-----the Lessons, Gradual and so on.
Later, having become used to saying these other parts at Low Mass-----in which he had to take the place of ministers and the choir himself-----he began to say them at High Mass too.Thus we have our present arrangement where the celebrant also says in a low voice at the altar whatever is sung by the ministers and choir. 18