* It was the first complete polyphonic setting of the Ordinary of the Mass. Before Machaut, composers typically set only individual sections of the Mass, like the Kyrie or Gloria. His "Messe de Nostre Dame" was a complete cycle, setting all the core parts of the Ordinary (Kyrie, Gloria, Credo, Sanctus, Agnus Dei).
* It was written in a highly sophisticated and innovative style. Machaut's Mass utilizes complex polyphonic textures, intricate rhythmic patterns, and innovative melodic lines. It showcases his mastery of musical composition and his ability to create a unified and cohesive work.
* It was a personal and highly symbolic composition. Machaut dedicated the Mass to the Virgin Mary, a reflection of his deep religious faith. The Mass also contains several personal references, including a possible self-portrait in the Agnus Dei.
In summary, Machaut's "Messe de Nostre Dame" was groundbreaking for its time, showcasing his musical genius and pushing the boundaries of compositional techniques. It is considered a cornerstone of medieval music history and a testament to Machaut's enduring legacy.