That's really really awesome! I love the dissonance, it's done so well it's hardly noticeable.

Who was this Dom. Charpentier, and when did he live?

And where did this chant appear prior to the SSPX's Traditional Roman Hymnal (2000)?

I am just raising the questions, because I've been under the impression for a number of years that this was less than ~100 years old, but I don't have evidence to back that up other than that I've never seen it in any source older than the above.

A similar chant is the Ant. Paradisi portae with Ps. Eructavit, as found in e.g. Cantus Selecti (1957) where it is no. 114. The notes in this edition are as follows:

Ant. II ad Matutinum in festo Assumptionis B. M. V. cum Ps. 44 super antiquam melodiam. Cfr. Revue du Chant grégorien, IV, 1896, p. 177-183. (Variae Preces, 1892, p. 192).

The history of the Angelus is not as well attested as many common Catholic prayers. It seems to have grown organically from a practice of saying the Ave Maria three times after Compline, a practice that is attested explicitly by St. Bonaventure (13th century). There are earlier mentions of saying a triple Ave Maria, though not explicitly associated with Compline (to my very fallible knowledge). In the 14th century the practice was officially instituted by Rome, and in the late 15th century, an indulgence was granted for praying the Angelus midday.

I had a hard time tracking down our friend Dom Charpentier, but located this footnote in an article on Tertullian: "Dom Charpentier, bénédictin de la congrégation de St-Maur, travaillait, en 1720, à une édition de Tertullien ; mais elle n'a point paru." (He was working on an edition of Tertullian, but it never appeared.) That quotation was the lynchpin, and with it you can track down other info about him, but basically, from what I can tell, he was an 18th century Benedictine academic. Later in life (much later, so he must have been a young man when he was working on Tertullian), on the eve of the French Revolution, he seems to have become the Prior of the Abbey of St. Benoit, and to have played some role in politics.

As for Mr. Ostrowski's ancient manuscript: What he found is not the earliest version. The likely earliest extant version is Einsiedeln, Stiftsbibliothek, Codex 611(89), beginning page 57v (at the very bottom and continuing on the next page). Look here:


https://www.e-codices.unifr.ch/en/sbe/0611/57v/0/Sequence-1025


It is believed (and I am not an expert on these manuscripts, so I'm just implicitly citing others, here) that it was copied directly from Guido of Arezzo's mss, which does, indeed, make it 'old' by most standards.

However, it is not clear to me what connection Ostrowski sees to the Angelus prayer or chant. Neither the melody nor the words are the same (or even similar). The chant in the manuscript is part of the Office for the first Friday of Lent ("FR VI") and almost certainly long predates the Angelus prayer (see above).

But probably I just don't see what he sees. The post that you linked from him is very brief. Perhaps he will chime in.

So Regensburg gives these examples http://gregorianik.uni-regensburg.de/an/#id/740 . I imagine that it was Dom Charpentier who suggested that it would fit Angelus Domini annuntiavit ... .
The book translated & extended by Moran is available here.

This is a delightful work! The music is awesome and the recording is excellent too. Bravo!

I am getting neumes dancing around in front of my eyes, but is this not the tune? The Einsiedeln, Stiftsbibliothek, Codex 611(89) manuscript version (linked by Michael Dickson) is different from most of variants shown in Antiphonale Synopticon.