Such a masterpiece, Henry! I definitely savored the beautiful harmonies in the chant section, and the fugato passages, as I'm a bit of a counterpoint buff. At first I was worried about the coherence of the movement as a whole, but I can tell that you put in a lot of hard work in to develop existing material in a convincing way. I also like the accumulation of historical techniques from organum to fugue to more dissonant (quartal?) harmony, spanning and summing up many centuries of music history.
All my compliments, and know that I sincerely admire your work!