This must be how the angels sound! That is the often evoked response of listeners to this exemplary quartet who explore, research, and bring to life medieval polyphony and chant. The blend of voices and virtuosity of creation is unparalleled by any other singers on earth. Once again, by research, the 4 have created a mass, this time "A Mass For The End Of Time." The end of time refers to the Last Judgement which is most strongly expressed in the liturgies of the Advent season, the Requiem mass, and the feast of Jesus's Ascension celebrated forty days after Easter. This work is based on the Ordinary and Proper chants of the Ascension mass with added tropes (newly written text and music) to enhance the feel of the music. Historically, the approach to the first millennium saw the collapse of Charlemagne's empire and alliances which yielded a tremendously unsettled period in European history. The church under the charismatic leadership of Pope Sylvester II created a spiritual anchor. Great cathedrals were begun and Christianity was seen as a primary civilizing influence. Musically, the traditional Roman plainchant was being renewed and greatly enlarged while developments in music such as staff line notation allowed these new creations to be rapidly learned and disseminated. Though the church provided a dynamic anchor, it also tended to foster a millennial belief in the end of time and that the Last Judgement was at hand. From this milieu, Anonymous 4 has recreated another incredibly beautiful liturgical testament.