Keith, I'm not sure to what Fransisco is referring, but I think of ancient instruments as various wind, string, and percussive instruments that are no longer in common use. I think of my Gregorio Paniagua recordings on the Harmonia Mundi label for instance. They sound great and are full of harmonic content, but I never hear them live. Viola de Gambo, harpsichord, some flutes.
We can get a nice idea of the instruments being played in this recording in this youtube video
Now imagine all this people in your room!