- 5 January, the eve of the Feast of the Epiphany, which is thetwelfth day after Christmas. Formerly this was a time of revels andmerrymaking, when plays and masquerades were performed. The traditionmay derive from the ancient Roman Saturnalia, which was held at thesame season. The Mummers' Play and its numerous regional variantsare particularly associated with Twelfth Night. see also PloughMonday.