Final answer:
The "Kyrie" from the L'homme Armé Mass was composed by Renaissance composer Josquin des Prez.
Step-by-step explanation:
The "Kyrie" from the L'homme Armé Mass was written by Josquin des Prez. This piece is a part of a cyclic mass that was very popular during the Renaissance period, where multiple movements of the Mass Ordinary were set to music, using a pre-existing tune called L'homme Armé as its cantus firmus, or fixed melody. Josquin des Prez was a Franco-Flemish composer who significantly contributed to the field of polyphonic vocal music, and his "Kyrie" is a fine example of his mastery in counterpoint and harmony within the context of the sacred genre.