Originally a German folk song from the early 19th century, "O Tannenbaum" (fir tree). The German lyrics (by Ernst Anschutz, 1824) sing praises to the tree's reassuring evergreen beauty & durability, not to anything related to Christmas. As the custom of Christmas trees came into vogue in the 19th century, the song became associated with the holiday. Authorship of the English words is sketchy, the ones used here being a rough composite of one version created in the early 20th century.