Roman chant

Old Roman chant is the liturgical plainchant repertory of the Roman rite of the Early Christian Church . It was formerly performed in Rome, and, although it is closely related to the Gregorian chant,the two are distinct. The Gregorian Chant gradually supplanted the Old Roman Chant between the 11th century and the 13th century AD. Unlike other chant traditions (such as Ambrosian chant, Mozarabic chant, and Gallican chant), Old Roman chant and Gregorian chant share essentially the same liturgy and the same texts. Many of their melodies are also closely related. Although primarily associated with the churches of Rome, the Old Roman chant was also performed in parts of central Italy, and it was possibly performed much more widely.

The chant that is now called "Old Roman" comes primarily from a small number of sources, including three graduals and two antiphoners from between 1071 and 1250. Although these are newer than many notated sources from other chant traditions, this chant is called "Old Roman" because it is believed to reflect a Roman oral tradition going back several centuries.

There are several theories concerning the origins of Gregorian and Old Roman chants, but one prominent hypothesis, supported by Apel and Snow, posits that both chant traditions derive from a common Roman ancestor in use circa 750 AD. In order to consolidate ecclesiastical power and strengthen their political ties to the power of the Roman church, the Franks, especially under the Carolingian rulers Pepin and Charlemagne, brought this older Roman chant north. There it was subsequently modified, influenced by local styles and Gallican chant, and categorized into the system of eight modes. This Carolingian, or Frankish-Roman, chant, became known as "Gregorian." In the meantime, the local chant remaining in Rome gradually evolved into the form in which it was eventually notated, at the same time that Gregorian was supplanting it in Rome.

...
Wikipedia