In a display of the imaginative programming that helped make Anonymous 4 more than just a collection of pretty voices, the New York-based female vocal quartet made an album for the year 2000 that looked back to the turn of the previous millennium. Building a mass around apocalyptic texts, A4 sings in a Frankified sort of Latin with some striking trills (one reviewer likened it to the cooing of a dove) — a surprising result of their research into 10th-century practice. Even more fascinating is how the Gregorian chant blooms into polyphony as the album goes on — try "Alleluia 2" and the various "troped" parts of the Mass (a "trope" is something added to or on top of an existing melody). Music around 1000 reflected the fears, hopes and questions that abounded in Europe then, and which would echo through the modern world as we approached Y2K. Much of this music survives in fragmentary form, at best, but the spirit that sparked it rings clear 1000 years later.