"Hark! The Herald Angels Sing" is a Christmas carol that first appeared in 1739 in the collection Hymns and Sacred Poems, having been written by Charles Wesley. A somber man, Wesley had requested and received slow and solemn music for his lyrics, not the joyful tune expected today. Moreover, Wesley's original opening couplet is "Hark! how all the welkin rings / Glory to the King of Kings".
The popular version is the result of alterations by various hands, notably George Whitefield, Wesley's co-worker, who changed the opening couplet to the familiar one, and Felix Mendelssohn. A hundred years after the publication of Hymns and Sacred Poems, in 1840, Mendelssohn composed a cantata to commemorate Johann Gutenberg's invention of the printing press, and it is music from this cantata, adapted by the English musician William H. Cummings to fit the lyrics of "Hark! The Herald Angels Sing", that propels the carol known today.