This is one of the best anthologies of its kind that I know and it comes not from the expected source of one of the many fine English vocal ensembles specialising in polyphonic, Renaissance music, but rather from perhaps the finest American group, Denis Keene's Voices of Ascension, currently celebrating its twentieth anniversary. They offer impeccable tuning in a very clear acoustic, singing music spanning a period from over 900 years ago by Hildegard of Bingen to the "Crucifixus" of Antonio Lotti, not properly of the period but a Baroque composer here writing in an already retrospective mode. My favourites include the sublime simplicity of the Farrant/Hilton(?) "Lord, for thy tender mercy's sake" and Byrd's "Ave Verum Corpus", but every piece is sung with poise and devotion. A beautiful collection, which covers not only 600 years of music from the Middle Ages to Baroque but also a variety of styles from Gregorian chant to complex anthems, and also spans the liturgical year, all arranged in no particular order other than to provide an emotionally satisfying and varied sequence. German, French, English, Dutch and Italian composers feature in a huge diversity of music united by its inner, transecendent quality. This disc is now available very cheaply on Marketplace. Buy it.