Often known as the Twelfth Night in the English-speaking Christian world, Þrettándinn (directly translated as “the thirteenth”) marks the end of Iceland’s epic Christmas season. The last of 13 straight days of Christmas merry-making, January 6th is the season’s last gasp—and not just because it’s the last day that you can legally shoot off fireworks in Iceland, or the last day you can purchase Christmas beer. No, according to folk traditions and tales, Þrettándinn is much, much weirder, and gloriously so: it is a time of talking animals, aquatic metamorphoses, naked dancing, supernatural gifts, and precognitive dreams. It is what Helga Einarsdóttir, the Museum Educator at the National Museum of Iceland, calls a liminal time or “a border between two worlds”—namely the holy season around Christmas and the back-to-normal New Year which is just beginning. So here are thirteen things you should know about Þrettándinn:
1. Þrettándinn is “Old Christmas”
Around 1528, the Roman Catholic Church decided to shift from the Julian calendar, which was instituted by the Romans around 46 BC, to the Gregorian calendar, which is still in use today. The Julian calendar attempted to approximate the solar year, but minor inaccuracies in the calendar structure—basically, a few minutes not accounted for in the solar rotation—lead to a gain of roughly three or four days every four centuries. This meant that important Catholic holidays, like Easter, tended to drift over time, which the church didn’t like at all. Thus the shift to the Gregorian calendar, which has fewer leap years, and which, by the time it was finally implemented in Iceland in 1700, had 11 fewer calendar days than the Julian calendar.
In practical terms, what this means is that holidays shifted significantly after the arrival of what 18th century Icelanders referred to as the “new style” calendar. So Christmas went from taking place on January 6th to taking place on December 25th. And so, as late as the end of the 19th century, Þrettándinn was known as “Old Christmas.”
2. Þrettándinn is also Second New Year’s Eve
What with all the confusion about calendar shifts and dates, a lot of holiday-related folklore got muddled along the way. So many of the supernatural occurrences and traditions originally associated with New Year’s Eve in Iceland have shifted over time to Þrettándinn. “The last day of Christmas has also often served as second-string New Year’s Eve,” writes ethnologist Árni Björnsson, “when celebrations can be held if the weather on New Year’s Eve is unfavourable.”
3. It’s time for bonfires and elf dances
Icelanders make the most of New Year’s Eve and Þrettándinn, indulging their pyrotechnic sides: large bonfires are regularly held on both New Year’s Eve and Þrettándinn. The bonfires celebrate all of the fairies and elves who are said to be departing on Þrettándinn, and many local celebrations elect Fairy Queens and Kings who lead ‘elf dances’ around the fire. Elf dance traditions may originate with a popular play called “Nýársnóttin,” or ‘New Year’s Eve,’ which was written by Indriði Einarsson in 1907 and first featured the King and Queen of the elves.
4. Þrettándinn is a good time for dreams
Þrettándinn also marks the start of Epiphany, the Christian holiday that commemorates the night in which Jesus’s birth was revealed to the Three Wise Men in a dream or vision. And so, in some local traditions, such as on the Northern island of Grímsey, Þrettándinn is known as “The Great Dreaming Night.” The dreams that you have on this night must be taken very seriously, as they may hold clues to the future.
5. Cows talk on Þrettándinn
On the evening of Þrettándinn, many folktales say that cows can suddenly speak. But while there are many variations on this story—in some versions, for instance, they specifically speak Hebrew—one thing is for sure: if the cows are talking, you don’t want to be listening. In one version collected by Jón Árnason (Iceland’s one-man Brothers Grimm), a cowhand hangs around in the barn after his work is done on Þrettándinn. Around midnight, the cows all stand up and begin to speak to each other in nonsensical rhyming couplets, which are supposed to drive anyone who overhears them crazy. The cowhand escapes before he fully loses it, but is obviously unable to prove his tale to anyone the next day. In other variations, however—such as one taking place on New Year’s Eve—the cowman is not so lucky, and goes mad listening to creepy bovine poetry.
6. Seals take on human form, get naked and get down
There are many folktales about seals transforming into humans on New Year’s Eve and Þrettándinn. In one fascinating variation, seals are actually the animal incarnations of an ancient Pharaoh’s army, drowned in the Red Sea while chasing Moses and the Jews out of Egypt. The drowned soldiers became seals, but their bones remain much like human bones. So once a year, they become human, shedding their skins and dancing naked on beaches.
In one very famous tale (also collected by Jón Árnason), a man goes walking on a beach and sees many seal skins lying on the shore. He takes one home with him and locks it in a chest. Later, he discovers a beautiful naked woman crying on the same beach because he’s taken her skin and she cannot return to the sea. He takes her home, marries her, and they have many children, but he keeps the seal skin locked away so that she can never escape. One day, however, he forgets to take the key to the chest, and the woman retrieves her skin and returns to the ocean.
7. Þrettándinn is moving day for fairies and elves
Þrettándinn is often thought to be the day in which fairies and elves leave their current dwellings and find new homes. In some traditions, residents walk around the home asking for the family’s continued well-being while those spirits who have arrived to come in, and those who want to leave go on their ways.
8. It’s the last day to see a Yule Lad
Þrettándinn is a time to “say goodbye to the spirits,” says Folklorist Terry Gunnell. So as the fairies take their leave and the elves move house, so also is the last Yule Lad leaving town. Iceland’s thirteen Yule Lads arrive one by one on the days leading up to Christmas, and then also leave one at a time on the thirteen days following. The last Yule Lad to leave is Kertasníkir, or “Candle Beggar.”
9. It’s a good time to sit at a crossroads
If you want a chance to meet one of the magical beings flitting around on Þrettándinn, your best bet is to sit at a crossroads and wait. In many folktales, people who sit at crossroads are met by elves who give them gifts of gold, food, or second sight. In some stories, the elves will tempt you with gifts all night, but you must not accept them. If you can last the night having accepted nothing, the elves will leave all their treasures behind for you. If you take the gifts before daylight, you may go mad. But usually, Terry says, “if you treat them well, they’ll treat you well. It’s a business transaction.”
10. Water is magic
Some folktales have it that water will turn to wine on Þrettándinn, while others suggest that dew is particularly potent and powerful on this day.
11. The unknown is made visible, sometimes at a cost
“If something is hidden from you,” says Helga, “it will open up to you on Þrettándinn.” In one exemplifying tale, a shepherd has particular success keeping his animals through the winter. He repeatedly disappears throughout the season, never telling anyone where he has been. One Þrettándinn, a curious farmer follows the shepherd, and finds that he has been travelling to a hidden mountain valley, which is still green even in the dead of winter. But this discovery comes at a cost: one of the valley dwellers curses the farmer for his curiosity and he dies three days later.
12. It’s the last day for Christmas decorations
You’re probably tired from all the bonfires and merry-making, but don’t slack off and leave your Christmas trees and decorations hanging around the house for the next month. It is considered bad luck by some to keep your Christmas paraphernalia up after January 6th.
13. It’s time to burn out, eat up, and play out Christmas
Traditionally, Þrettándinn is the last day for people to get their fills of Christmas decadence. So Icelanders would “burn out” Christmas by finishing off the remains of their candles, “eat up” the season by finishing all the leftovers, and “play out” the day with long card games.