In the broad sense, "Gallican" identifies all the Western rites outside of Rome (and its dependent province of Africa, about which nothing is known). The Gallican rite and its chant, properly speaking, originated with the Gallo-Roman people. In the fifth century the Arian Visigoths overran southwestern Gaul and the pagan Franks moved into northern Gaul. The intervening area, the last remaining part of Roman Gaul, was conquered by the Franks in 486, and early in the sixth century they completed their conquest of present-day France by driving the Visigoths into Spain. In the meantime King Clovis was baptized a Catholic at Reims in 496 or shortly after. The Franks adopted the Gallican rite, leaving the remaining Gallo-Romans much autonomy in civil and religious affairs. Their church possessed a proud history, notably St. Hilary of Poitiers, St. Martin of Tours, and several poets such as Venatius Fortunatus.
The survival of Gallican chants is a subject of some dispute. The suppression of the Gallican rite after about 800 is noted under the heading of Gregorian chant. Reasons for identifying specific chants as Gallican rely on several arguments. Some feast days, such as the Minor Litanies (the three days before the feast of the Ascension) and St. Martin of Tours, were not celebrated in Rome, so the chants found in medieval Gregorian notation are presumed to have survived from the Gallican rite.
Another argument is based on literary style. Roman prayers and chant texts were always notably concise and spare. All other Western rites display a more oratorical style of declamation, rich in imagery, with chants marked by melismatic flourishes (long series of notes on one syllable). Such Palm Sunday processional antiphons as Collegerunt and Cum audisset are thus considered to be Gallican chants.
A third argument is based on the resemblance of certain presumably Gallican chants to Mozarabic and Milanese chants. Kenneth Levy has recently shown that offertories that use texts not drawn from Psalms (the non-psalmic texts) are lacking in Old Roman sources but similar to each other in the three non-Roman sources just mentioned.
The Gallican origin of certain of these chants is evident from the fact that the earliest Frankish manuscripts, copied directly from Roman sources, omit them, while later Frankish manuscripts include them. It follows that these chants, not found in sources brought from Rome, were added later from local sources to keep them from being lost. This was more easily done in places removed from the center of authority. Manuscripts of eleventh-century Aquitanian origin contain a notable number of presumably Gallican chants. The Franks also composed new chants, and these share traits of both Roman and Gallican style.
In any case, Gallican liturgy was not unified but probably employed variant forms throughout the region, and we have no body of Gallican chant sources surviving (as we do with Beneventan and other chants). Several recordings bearing the term "Gallican" in their titles are sung from Aquitanian manuscripts.
The seventeenth-century effort of the French to return to their origins resulted in the composition of a Neo-Gallican liturgy with chant. This has no relation to the present subject and is discussed as a species of Gregorian chant in that article.