Interesting. Indeed, the instrumentation (while now notable for simple novelty) lagged way behind the music of the time.
Our choirmaster is an early music fan (he took his master's at Oregon, which is Early Music Central) and he's determined to have us sing a complete DuFay Mass someday . . . if you're used to singing modern music the early stuff will throw you for a loop. The harmonies and everything are SO different. And it sounds strange to modern ears - strange but beautiful.