Gregorian chant was established as the chant repertory of the Carolingian Empire, the dominant political power in the late eighth and ninth centuries, and this ensured its survival through the rest of the Middle Ages and, in various transformations, down to the present. Which is how Gregorian chant comes to occupy a central position in this book. But it was not the only sort of medieval chant. In the Latin West other chant repertories were sung for Latin rites independent of Rome. And in the Eastern Roman Empire yet others – the chant of the rites of Jerusalem, Antioch and Constantinople, the Georgian and Armenian rites, and various types of Slavonic chant – achieved a greater or lesser degree of fixity, enabling us to study them today. Even if they cannot be described in detail in this short book, their existence should be borne in mind as a parallel to the Gregorian chant repertory dominant in the West.

The Christian church in the late Roman Empire; Rome and the Franks

The early centuries

Gregorian chant is the musical element in a rich ritual, a ritual developed and performed by a stable religious community. Instability threatens or destroys the tradition, if things cannot be remembered and repeated year after year. The stable conditions in which chant could flourish were achieved in principle (if not everywhere in practice) after Christianity was recognized as one of the official religions of the Roman Empire under Constantine the Great (324–37).