In the commentary of the catalogue Fragmenta Codicum (see Bibliography) László Mezey surmised that both fragments (F 780, 790) originate from the same monastic (Benedictine) antiphonal. Indeed, the part from the commune sanctorum transmitted on the fragments is completely consistent with the repertory and chants written in the antiphonal D-Mbs Clm 4304 from the Benedictine monastery St Ulric and Afra in Augsburg (see CANTUS: https://cantusdatabase.org/source/123682), the facsimile of the manuscripts is accessible here: https://www.digitale-sammlungen.de/en/view/bsb00060183?page=,1).
Gabriella Gilányi
Zsuzsa Czagány