Resources for medieval musicology and liturgy
Please have a look on a paper which has been finally published last year:
The scholarly interest of the liturgy of Jerusalem resides in at least three points.
First, the Hagiopolite liturgy was central among the various rites observed in the ancient Church, thanks to the spiritual and ecclesiastical status of the holy city of Christendom, endowed with innumerable sacred sites.
Secondly, the rite of Jerusalem lies at the roots of the Byzantine rite, together with that of Constantinople, as one of the two constituents of the Early-Byzantine liturgical synthesis that is usually called the Byzantine rite.
Thirdly, preserved sources of the Hagiopolite rite are comparatively numerous. While for the rites of the two most important political centres of the Roman Empire, Rome and Constantinople, few sources are available before the 8th century, for the rite of Jerusalem we dispose of a great number of excellent sources from Late Antiquity.
Indeed, it might seem that the essential part of all pre-Islamic (before 638) liturgical books of Jerusalem have been preserved, although only very little in Greek, their original language. Taft’s ‘Law of the paradox of the conservative periphery’ applies here. Notably the Caucasian periphery, that is, the Armenian and Georgian churches, has contributed the most to preserving the late Antique liturgy of Jerusalem.
Of these two, the Georgian witness is by far the most important, since while the Armenian witness is more or less limited to an archaic version of the Lectionary, the Georgian one appears to cover all the liturgical books of Jerusalem. For the Jerusalem liturgy of the 9th and 10th centuries, the situation is different, like for most other rites, as the Georgian and Armenian source material is supplemented by Greek, Syriac, Syro-Palestinia and Arabic manuscripts.