MUSIC

When Britten Met Haydn, Cecilia’s final concert of the season, presents a comparison in style and substance of works by both composers. Haydn’s St. John of God Mass—also known as the Little Organ Mass because of its obbligato organ part—and his rarely performed Salve Regina in g minor, a three-movement work for soloists, chorus and chamber orchestra, will be matched with Benjamin Britten’s Cantata Misericordium and the Serenade for Tenor, Horn and Strings, featuring young Boston tenor Aaron Sheehan.