were a signal for a similar bit of by-play with a linen cloth which lay upon the altar[10]: Maundy Thursday had its commemorative ceremony of the washing of feet[11]; while the _Tenebrae_ or solemn extinction, one after another, of lights at the Matins of the last three days of the week, was held to symbolize the grief of the apostles and others whom those lights represented[12]. These, and many other fragments of ceremonial, have the potentiality of dramatic development. Symbolism, mimetic action, are there. The other important factor, of dialogued speech, is latent in the practice of antiphonal singing. The characteristic type of Roman chant is that whereby the two halves of the choir answer one another, or the whole choir answers the single voice of the _cantor_, in alternate versicle and respond[13]. The antiphon was introduced into Italy by St. Ambrose of Milan. It had originated, according to tradition, in Antioch, had been in some relation to the histrionic tendencies of Arianism, and was possibly not altogether uninfluenced by the traditions both of the Greek tragic chorus and of Jewish psalmody[14]. At any rate, it lent itself naturally to dialogue, and it is from the antiphon that the actual evolution of the liturgical drama starts. The course of that evolution must now be followed. The choral portions of the Mass were stereotyped about the end of the sixth century in the _Antiphonarium_ ascribed to Gregory the Great[15]. This compilation, which included a variety of antiphons arranged for the different feasts and seasons of the year, answered the needs of worship for some two hundred years. With the ninth century, however, began a process, which culminated in the eleventh, of liturgical elaboration. Splendid churches, costly vestments, protracted offices, magnificent processions, answered especially in the great monasteries to a heightened sense of the significance of cult in general, and of the Eucharist in particular[16]. Naturally ecclesiastical music did not escape the influence of this movement. The traditional _Antiphonarium_ seemed inadequate to the capacities of aspiring choirs. The Gregorian texts were not replaced, but they were supplemented. New melodies were inserted at the beginning or end or even in the middle of the old antiphons. And now I come to the justification of the statement made two or three pages back, that the beginnings of the liturgical drama lie beyond the very borders of articulate speech. For the earliest of such adventitious melodies were sung not to words at all, but to vowel sounds alone. These, for which precedent existed in the Gregorian _Antiphonarium_, are known as _neumae_[17]. Obviously the next stage was to write texts, called generically ‘tropes,’ to them; and towards the end of the ninth century three more or less independent schools of trope-writers grew up. One, in northern France, produced Adam of St. Victor; of another, at the Benedictine abbey of St.