The appearance of the sequence in the history of medieval hymnody was an episode of the greatest importance not only in the evolution of Latin religious and secular poetry but in their vernacular counterparts. In order to understand the extraordinary popularity and wide diffusion of the sequence it must be emphasized that it is not just another hymn, but an ornament to the mass, individually created for each and every festival with a particular theme in mind. The seasons of Advent, Nativity, the Passion, Easter, Ascension, Pentecost, Trinity, the Virgin festivals of the Nativity, Annunciation, Visitation, Purification and Assumption, the feasts of the Apostles and other biblical Saints, the Martyrs, Confessors and Virgins formed a great series which challenged the finest efforts of the clerical poets. Herein lies the essential interest of this hymnody. The original Latin hymn was associated with daily secular worship and then with the canonical hours of the monastery. The sequence was associated with the celebration of the divine sacrifice. As a closing illustration for this chapter the Alleluiatic sequence has been selected. Based upon the canticle, _Benedicite omnia opera_, and often attributed to Notker, this superb sequence reaches a height of expression comparable to the noblest hymns of the ninth century revival. (See Illustrative Hymns, XII. _Cantemus cuncti melodum nunc Alleluia_, “The strain upraise of joy and praise.”) CHAPTER FIVE Late Middle Ages: Hymns and Sequences Beginning with the twelfth century the large number of new hymns and sequences produced point to a degree of creative activity that continued through the High Middle Ages. A recent historian of medieval literature, De Ghellinck, sees the religious poetry of the twelfth century rivalling the secular, and points out that ten thousand specimens of every type of religious verse, from 1060 to 1220, are edited in the _Analecta Hymnica_.[1] Maurice Hélin, whose attractive volume is available in English translation, considers the poetic product of the twelfth century the peak of Latin poetry and “its most original contribution to the intellectual patrimony of the west.”[2] It is easier to repeat such a statement than to present acceptably the relevant evidence in the field with which this chapter is concerned. One might expect a larger proportion of known authors but anonymity remains the rule. The exceptions command recognition among the most notable writers of hymns and sequences in any period of their production. I. Sequences of the French School