He composed some fifty Sequences. In his work, as well as in that of others after him, the device of words began to modify and develop the melodies themselves Sometimes Notker adapted his verbal compositions to those cadences or melodies to which the Alleluia had long been sung; sometimes he composed both melody and words; or, again, he took a current melody, sacred or secular, to which the Alleluia never had been sung, and composed words for it, to be chanted as a Sequence. In these borrowed melodies, as well as in those composed by Notker, the musical periods were more developed than in the Alleluia cadences. Thus the musical growth of the Sequences was promoted by the use of sonorous words, while the improved melodies in turn drew the words on to a more perfect rhythmic ordering.
Notker died in 912. His Sequences were prose, yet with a certain parallelism in their construction; and, even with Notker in his later years, the words began to take on assonances, chiefly in the vowel sound of a. Thereafter the melodies, seizing upon the words, as it were, by the principle of their syllabic correspondence to the notation, moulded them to rhythm of movement and regularity of line; while conversely with the better ordering of the words for singing, the melodies in turn made gain and progress, and then again reacted on the words, until after two centuries there emerged the finished verses of an Adam of St. Victor.
Thus these Sequences have become verse before our eyes, and we realize that it is the very central current of the evolution of mediaeval Latin poetry that we have been following. How free and how spontaneous was this evolution of the Sequence. It was the child of the Christian Middle Ages, seeing the light in the closing years of the ninth century, but requiring a long period of growth before it reached the glory of its climacteric. It was born of musical chanting, and it grew as song, never unsung or conceived of as severable from its melody. Only as it attained its perfected strophic forms, it necessarily made use of trochaic and other rhythms which long before had changed from quantity to accent and so had passed on into the verse-
