Alleluia ‘Dies sanctificatus’ is the Proper Alleluia for the Mass of Christmas Day and can be found in the early tenth-century Cantatorium from the library of the St Gallen monastery. One of the most important chant source manuscripts, the Cantatorium was used by the monks of Solesmes when they produced their nineteenth-century editions which enabled the restoration of Gregorian chant to the Catholic liturgy. Gregorian chants are often used to link together feasts, and so this second-mode melody is also used on the Feast of the Epiphany to recall the Nativity.

from notes by Charles Cole © 2020