its not necesserilly the most beautiful music ever created, but the thought behind every note is mindblowing.
i'd check out arianna lament
maybe cruda ammarilli which was in his 5th book of madrigals, and cause an outrage during his time because of the nontraditional treatment of dissonances. that caused him to coin the term, seconda practica, where basically everything is allowed because the music is the sevant to the words.
quite the avante garde for his period.
i also am liking salomone rossi, whi did early baroque music but in hebrew. he was the first to write polyphonic music to jewish prayers

thanks for this thread, i was listening hildegard yesterday and wondered about other stuff to listen to.