"Deck the Halls" (original English title: "Deck the Hall") is a traditional Christmas and New Year's carol. The "fa-la-la" refrains were probably originally played on the harp. The tune is Welsh dating back to the sixteenth century, and belongs to a winter carol, Nos Galan. In the eighteenth century Mozart used its tune for a violin and piano duet. The repeated "fa la la" is from medieval ballads and used in Nos Galan, the remaining lyrics are American in origin dating from the nineteenth century.