There is an undeniable confusion as to when Twelfth Night actually is – even Stephen Fry got it in a muddle on the Christmas episode of QI. So…
It is defined by the Shorter Oxford English Dictionary as “the evening of the fifth of January, preceding Twelfth Day, the eve of the Epiphany, formerly the last day of the Christmas festivities and observed as a time of merrymaking”. There is some confusion these days, however, as to which night is Twelfth Night: modern practice is often to regard the night of Epiphany itself (sixth of January) to be Twelfth Night. The older tradition of Twelfth Night being the 5 January stems from the medieval practice of the day beginning at sunset, rather than at midnight as it does now. Thus Twelfth Night falls on 5 January, ahead of Twelfth Day on the 6th.
So, I guess tonight is Twelfth Night, probably unquestionably, but you’ll notice today’s title is the eleventh… I guess because although in today’s world Night follows Day, this medieval tradition of the day beginning at sunset not midnight, means that tomorrow will indeed be the Twelfth Day of Christmas…