Having in my last post identified the musical source for the chant setting of the Offertory for the feast of St Philip Neri, I thought next to mention the melodic origins of the rest of the Proper of his Mass.
To begin with, the Introit, Caritas Dei, is self-evidently taken from the Mass of Whit Saturday, omitting the first, internal alleluia (and the last two, except in Eastertide), raising the first note of per by a tone and replacing the Whit Saturday melody for the last word, nobis, with that of the last two syllables of the first (itself identical with the corresponding part of the last) Whit Saturday alleluia.
Likewise, the Gradual Venite is taken without change from the Mass of the 7th Sunday after Pentecost.
The Alleluia and verse De excelso is set to the same melody as the first Eastertide Alleluia and verse for the feast of St Irenaeus (28th June), but it is unclear to me as to which is the original.
I have not yet found a source for the music of the second Eastertide Alleluia and its verse Concaluit.
Most interestingly, the Communion Cor meum is set to a very prominent chant – that of the Communion Viderunt of the Mass of Christmas Day. Doubtlessly this conveys something of the joy whereby the heart and flesh of such a saint do ever exult in the living God.