“O Little Town of Bethlehem” is a Christmas carol. Based on an 1868 text written by Phillips Brooks, the carol is popular on both sides of the Atlantic, but to different tunes: in the United States, to “St. Louis” by Brooks’ collaborator, Lewis Redner, and in the United Kingdom, Canada, and Ireland to “Forest Green,” a tune collected by Ralph Vaughan Williams and first published in the 1906 English Hymnal.