There has been some discussion in the comment boxes about Montederdi's Vesper's service of 1610, a piece that provides endless fascination because it serves as a kind of transition between two worlds, that of the Renaissance and the Baroque.
In so many ways, I hear this massive effort as experimental and delightfully progressive in some ways. One hears in its construction the passing of an old world and an entry into a new world - a transitional piece that is struggling with capturing the sounds of a new prosperity and changing artistic sensibility, an updating of the old in the manner that Bach did with hymns in a later period.
My top favorite piece from this work is the Sancta Maria, which has this remarkable blend of chant in the treble voices, very calm with long phrases, while underneath we have some extremely complex writing for viols and brass and other interesting instruments that have fallen out of use, and they are engaged in dazzling rhythmic and scale exercises that must be difficult to play on those cumbersome and volatile instruments.
The performance below is particularly interesting because it employs all these old instruments. We see the predecessors to the modern trombones, unusually shaped violin bows, and some other items that I don't recognize, such as these winds instruments that look like clarinets but do not use reeds and so sound like trumpets but cooler. I'm sure some readers can enlighten me.
Anyway, if you have never heard this piece before, you are in for a great treat. Follow the repeating motifs in the trebles and listen carefully to what is going on underneath, in the midst of dramatic time signature changes. For the time, this must have sounded completely new. Thank you to the amateur video maker and the Eindhoven Vocal Ensemble.