It's often said informally that the Mass formularies, as in the Liber, with their assignments such as “For Double Feasts, 3” are not normative.
On the other hand Paschal and Requiem Masses are strongly associated with certain melodies: almost normative.
Is there any history to read about how the 18 (?) (or 16?) formularies in the Liber came to be assembled, and more to the point, the background and traditions of assigning particular ordinary chants to Masses and seasons?
On the other hand Paschal and Requiem Masses are strongly associated with certain melodies: almost normative.
Is there any history to read about how the 18 (?) (or 16?) formularies in the Liber came to be assembled, and more to the point, the background and traditions of assigning particular ordinary chants to Masses and seasons?