From the Christmas Carol Songbook:
cantorion.org/ ... tmas-Carol-Songbook-Voice-SATB

"Deck the Halls" is a traditional Christmas carol. The melody is Welsh, dating back to the sixteenth century, and belongs to a winter carol, "Nos Galan", while the English lyrics, written by the Scottish musician Thomas Oliphant, date to 1862.
The above text from the Wikipedia article "Deck the Halls" text is available under CC BY-SA 3.0.