The ancient music we know as ancient (Tallis Scholars, Hilliard Ensemble) has more ancient past in the shape of the Pro Cantione Antiqua. The formula is simple: take a few good singers and have them sing ensemble. Among the cadets of this outfit are a few OK choir boys you may have heard of: Paul Esswood, Michael Chance, Ian Partridge. (Yeah, they did move on to other things later). The sound the group made is unspeakably beautiful. I have always been partial to Palestrina, but this -- well, this is something else altogether.