Gallican Chant refers to a body of very early Christian chant utilized in the Frankish kingdom of Gaul before the advent of unified Gregorian services. It was greatly variable in terms of liturgy, subject, and music, and the content of Gallican services could differ widely throughout the region of Francia and other Frankish-controlled lands, a situation that was of great concern to the Roman church in the first millennium C.E. There have been numerous theories raised as to the origins of the Gallican rite; in the nineteenth century, Anglican theologian William Palmer projected its origins to the second century C.E. and suggested that the rite originated with the Church of Ephesus. Although some common elements between the liturgical practices of Eastern Churches and the Church of Gaul did exist, this, and other theories, has since been rejected. Nevertheless, the Gallican rite existed by 465 C.E., as that year the Council of Vannes was called, in part, in order to deal with the Church of Gaul's obvious division of purpose from Roman practice.
The Gallican rite, and its chant, dominated the services held in Merovingian-held lands through the 750s. In 751, King Childeric III was deposed, ending the Merovingian dynasty and sweeping the Carolingian dynasty into power. Roman services were introduced into the former Merovingian lands in about 760, and by the time Charlemagne took power in 768, the Gallican rite was effectively expunged from Christian churches in Francia. As the Gallican rite had been adopted by the Visigoths, who spread its use as far south as Toledo; some elements of it remained within Mozarabic services a good deal longer -- when Charles the Bad expressed a desire to hear the Gallican service sung in the 850s he had to summon monks from Spain who still knew it. Some remnant of Gallican practice were likewise retained in Celtic lands as well.
Eight fragments of Gallican service books, mostly dating from the early Carolingian period, are all that remain of a liturgy that was observed throughout Western Europe for four centuries. None of these sources contain music; indeed, when they were made, music notation was in very limited use and inexact in terms of pitch and rhythm. However, the liturgy that was handed down through Charlemagne did not address every possible option in terms of services, and in many localities, churches silently elected to retain pieces written for special services held in honor of local divines. This process did not happen overnight, but by the eleventh century Gallican chant melodies, and even some liturgical pieces such as the Preces, began to creep back into the service books of otherwise Ambrosian, Mozarabic, and especially Gregorian orders. Some of the special pieces for local divinities continued to be used until the end of the middle ages. The identification and recovery of chants of Gallican origin from chant manuscript sources continues to be a major concern for scholars in the field of medieval music; certain works of Gallican origin are of incredible antiquity, verified in independent sources as going back to the fifth century C.E.