Old Roman Chant is a retrospective term that identifies a specific part of the historical chant repertory represented in five manuscripts only -- CH-CObodmer C74, I-Rvat lat.5319, I-Rvat S Pietro V 79, I-Rvat S Pietro F 22, and GB-Lbl Add.29988. The earliest manuscript dates specifically to the year 1071, and the latest from the middle of the thirteenth century. Not recognized as belonging to a separate class of chant until the 1890s, a variety of viewpoints as to the origin and purpose of Old Roman Chant have been advanced since about 1950, particularly in regard to how it may represent the lost, "original" repertoire of chant first introduced in the eighth century. What is now referred to as Gregorian chant is known to have been refined from earlier, pre-Gregorian chant repertoire as refined in the churches of Gaul and adopted -- to exclusion of other styles of chant, save Ambrosian -- wholeheartedly by the Vatican in the thirteenth century.
In the -- apparently -- final consensus, Old Roman Chant is postulated as a style of chant observed in local Roman churches before the Gregorian curtain rang down, and that some of the music was still in use for at least some time afterward. Rather than being representative of the corpus of eighth century earliest Christian chant -- as was speculated at one time -- Old Roman Chant is yet another refinement of that material, just like Gregorian. While the settings of the Mass are similar to that of Gregorian, the major differences are in the Office. Old Roman Chant observes much longer melismas than in standard Gregorian chant and has a slightly different feeling of tonality, as until Gregorian was adopted in Rome, the Gregorian system of eight psalm tones was apparently unknown to the Romans. The practice of singing Old Roman Chant died out probably not later than the dawn of the fourteenth century. ~ Uncle Dave Lewis , Rovi