So naturally, I went to Mr. Vianini's YouTube Channel and did a quick search on inno (Italian for "hymn"). And here it is; there are at least 50 hymns here, many of which I've posted about on this blog. Most are Gregorian chant, but he posts Ambrosian chant, too, and perhaps other forms; I haven't had a chance to go through everything yet.
These are all in Latin, and let me say again what a terrific resource this is. I get updates about once a week listing new posts, too; if I were you, I'd go there at once and subscribe so you get those updates, too.
Here's a great page, for instance: it's the hymn Aurea luce , which is, I'm sure you'll recall, sung on the June 29 feast day of Ss. Peter and Paul, and which was written by "H. Elpis, wife of Christian philosopher poet Anicius Manlius Severinus Boethius." That's way back there around the year 500 or so.
Here's the image I posted, with a snippet of the hymn at the bottom of the page:
And yes indeed, that's the melody that Mr. Vianini is singing here:
Terrific! These seem to be the Latin words:
Aurea luce et decore roseo,
lux lucis, omne perfudisti sæculum,
decorans cælos inclito martyrio
hac sacra die, quæ dat reis veniam.
lanitor cæli, doctor orbis pariter,
iudices sæcli, vera mundi lumina,
per crucem alter, alter ense triumphans,
vitæ senatum laureati possident.
O Roma felix, quæ tantorum principum
es purpurata pretioso sanguine,
non laude tua, sed ipsorum meritis
excellis omnem mundi pulchritudinem.
Olivæ binæ pietatis unicæ,
fide devotos, spe robustos maxime,
fonte repletos caritatis geminæ
post mortem carnis impetrate vivere.
Sit Trinitati sempiterna gloria,
honor, potestas atque iubilatio,
in unitate, cui manet imperium
ex tunc et modo per æterna sæcula.
I think the first phrase of the second stanza is referring to "Heaven's Janitor"! (That would probably be Peter, who after all is the owner of all those keys.)
I posted the English words to a similar hymn, revised from this one, at the link above; here they are again, although there seems to be a verse missing in these:
With golden radiance bright, with fair and ruddy glow,
The Light of Light its beams o'er all the earth doth throw:
This holy-day, whereon to sinners hope is given,
The glorious Martyrdoms give joy to highest heaven.
Earth's teacher, and the guard of heaven's eternal gate,
True lights of all the world, earth's judges dread and great,
The sword-stroke, and the cross to them their victory give,
And now, with laurel crowned, in heaven's high court they live.
O happy city Rome, the precious life-drops shed
By these two noble chiefs thy walls have hallowed,
By nought that is thine own, but by their deeds of worth,
Thy fairness far excéls all beauty else on earth.
Now to the Trinity eternal glory sing;
All honour, virtue, might, and hymns of gladness bring;
He rules the universe in wondrous Unity,
And shall, through all the days of vast eternity. Amen.
The missing verse seems to have something to do with olives or olive trees - and perhaps can be filled in in that regard by raiding the other hymn sung for this feast, Felix per omnes festum mundi cardines, which calls Peter and Paul "two olive-trees that stand before the Lord."
I also spy several Lent and Easter-season hymns on these pages, so you'll be hearing from me (and Mr. Vianini) again quite soon, I expect.