The Kyrie Trope
There was frequently some option as to what would be sung for the trope to the Introit, say, or the Kyrie or the sequence. The most recent investigations have nearly all drawn a line between the syllabically texted Latin Kyrie and what is a more complex form, with a musically independent trope placed before or interpolated among the phrases of a Kyrie. The credit for clarifying the difference between Kyrie with trope and Kyrie with text belongs above all to Melnicki. Her catalogue of Kyrie melodies forced the distinction, by its attention to the musical forms involved. Only one Kyrie trope, Deus solus et immensus, has both East and West Frankish sources. As with Omnipotens genitor lumenque, the version from German territory has the eight-element form typical of that region, while elsewhere the form is variously reworked into versions that are both clearly derivative and irregular.