The professional musicians of the central Middle Ages who were charged by their churches with the celebration of the liturgy shaped the music for it according to institutional needs, available performing resources and their own tastes. Differing combinations of these factors generated the need for new music, which allowed these musicians the opportunity to exercise their creative abilities. Such opportunities carried great significance in a culture that valued, above all, tradition and continuity, and suspected innovation. In this regard, the canon of the Council held at Meaux in 845 is revealing. It condemns the singing of Gloria tropes and texted sequences following the Alleluia, calling them novelties (“novitatibus”). Even if this text is not authentic (and the evidence is inconclusive either way), it occurs in an early tenth-century manuscript, and so, at the very least, reflects the thinking of ecclesiastical officials around the year 900.

Yet the occasion arose for these professional singers to produce new compositions, whether from their own desire to express themselves, or from institutional policy. During the ninth and tenth centuries, following the adoption of Roman chant in the Frankish kingdom, the principal focus of compositional activity seems to have been the new genres of tropes and sequences, as the canon of Meaux mentioned above suggests. Arguably the most important composer in the period immediately before the turn of the millennium is Notker Balbulus (†912), of the abbey of Saint Gall, best known for his sequence composition.