In the Offertorium Iubilate deus omnis terra as notated in a 12th century fragment kept by the Staatsbibliothek Berlin, an almost orgiastic compilation of musemes highlights the word “ipse” in the phrase quia dominus ipse est deus.
If we accept the assumption that musemes ALWAYS have an indexical function in relating melody to verbal content of a chant, these stacked musemes tell us something. If this offertorium indeed was composed by Alcuin as some scholars assume, we may assume that they refer to the Spanish adoptionist heretics Elipandus of Toledo and Felix of Urgel.
De Codes van het Gregoriaans 