From the description:
The Kyrie from the Missa Cantata for the Feast of St. Michael the Archangel. The Kyrie is taken from William Byrd’s Mass for Three Voices and was reworked into a 9-fold Kyrie for the Mass.
The choir for the service is made up of seminarians from Holy Cross School of Theology in Brookline MA, lead by the parish organist and choir director, Ian Abodeely.
The service was held at St. Stephen Orthodox Church (Western Rite) in Springfield, Massachusetts, a parish of the Antiochian Orthodox Christian Archdiocese of North America.