The Ceremony of Carols by Benjamin Britten was inspired by his discovery of “The English Galaxy of Shorter Poems.” The composer originally intended to write a harp concerto, but instead produced this work for treble voices and harp, using “carols” mostly written by 15th- and 16th-century writers. It’s our Evening Masterwork tonight at 7, on Christmas night: Britten’s Ceremony of Carols on Classical WSMR 89.1 and 103.9.