HISTORY
The History of the Feast can be found in the excellent Liturgical Year, by Dom Prosper Guéranger.
PROPERS
The music of the Propers is explained in The chants of the Vatican Gradual, By Dominic Johner, OSB
ORDINARY
Asperges, Mass XVII and Credo I
MUSIC
Chant notation from the GABC Propers tool.
EXTRA MUSIC
Trope. Sanctissimus namque Gregorius
Mysterium Ecclesiae, Ambrosian advent hymn
O salutaris hostia,
Gaudete Flores Martyrum, Hymn from the Mozarabic Breviary, We have been unable to find authentic melodies for these Hymns, so have set them to melodies used for Advent Hymns found in the Augsberg Antiphonal 1580 A.D.
Domine Salvum Fac third melody