 The hymn tune Mendelssohn – an adaptation by William Hayman Cummings of a melody from Mendelssohn 's cantata <unk> ( Festive Hymn ) – is the standard tune for Charles Wesley 's popular hymn Hark ! The Herald Angels Sing . This extract from an originally secular 1840s composition , which Mendelssohn felt unsuited to sacred music , is ubiquitous at Christmas . 
