The Boston-based professional vocal ensemble Blue Heron performs works by Johannes Ockeghem and Johannes Regis at First Church in Cambridge, Congregational on October 17, 2015. This was the third concert in the ensemble's project to explore the complete works of one of the finest composers of his, or any time. Johannes Ockeghem (c.1420-1497) Missa L'homme armé: Agnus dei & Gloria --- BLUE HERON perform Ockeghem live this Sat. Oct. 14- Ma Maistresse-Songs, Masses, and a Motet for my Lady. Ticket giveway!