One of the most popular chant mass settings sung today is known as Missa de Angelis or Mass of the Angles. It is mass VIII in the Vatican edition. Here is a link to a Youtube video of this mass. https://www.youtube.com/watch?v=dG-gOLUnAN0&list=PLEz4GufIuIEaXyx9zBXdKy5X_Jzbsa92s
Most of the Gregorian chant masses in the Graduale Romanum get their names from tropes that were sung as a part of the Kyrie. A trope by the way is a verse that was sung before or inserted in the text itself. One example of this is the popular Missa Orbis Factor. It is so called because its trope was “orbis factor rex aeternae” creator of the world, eternal king.
The Missa de Angelis, however, most likely received it’s name from a more unlikely source.
This title of “Mass of the Angels” comes from the devotion, established in general use through the efforts of the Franciscans, of celebrating, on Monday, a votive mass in honor of the Holy Angles. (A. Gastoue, The Caecilia, Vol. 60, no. 12, Dec. 1933)
The Franciscans went about collecting the parts of this mass (Kyrie, Gloria, Sanctus, Agnus Dei) and in part have helped to establish its name since the 16th century.
Interestingly enough, it was never custom until more recently to sing Mass VIII on a Sunday. This setting, by the 18th century, was exclusive to votive masses and certain degrees of feasts. The Kyrie, Sanctus, and Agnus Dei are the oldest parts of the mass and enjoyed popularity in the late middle ages. The Gloria though is quite new as far as chant goes. Documentation for it only goes back as far as the early 15th century. This accounts for its major sounding mode, which doesn’t at all lend itself to the natural accents of the Latin language. Nevertheless, it is a well known and enjoyed Mass setting.