An ensemble dedicated to the performance of unaccompanied choral literature from the Medieval period to the present, Kairos will offer two evenings of music this month at Holy Cross Monastery in West Park. On December 4, Kairos presents Bach’s Advent Cantata No. 36 fifth concert in Kairos’ 2011 Bach Cantata series, at 4pm. The service will also include several movements from William Byrd’s Mass for 4 Voices and a set of pieces by Italian Baroque composer Giovanni Gabrieli for solo cello, performed by cellist Susan Seligman. The group will offer its annual Lessons and Carols Service on December 18 at 3pm. The service will include readings from the Old and New Testaments, interspersed with choral motets, hymns, and carols. Dr. Edward Lundergan is the artistic director of Kairos. www.kairosconsort.org.