Yes, it's more than Shakespeare. Twelfth Night, the eve of January 5, is an English folk custom for the end of Christmas merrymaking and in ancient Celtic tradition the end of the 12-day winter solstice celebration. On Twelfth Night, it was customary for the assembled company to toast one another from the wassail bowl. In Old English, wassail means "Be in good health," but the term also was applied to the drink itself (usually spiced ale).
Try the Old Farmer's Almanac's Light Wassail recipe.
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