Why is Friday the 13th considered unlucky?
Nobody knows for sure, but we’ve got some pretty good theories.
It’s likely that Friday the 13th is seen as unlucky for multiple reasons. While the number 13 has been seen as unlucky for centuries (at least in the Western world), the specific superstition of Friday the 13th is much more recent.
Here are a few facts that help to explain the origins of the idea that Friday the 13th is the unluckiest date on the calendar:
Fear of the number 13 might have roots in Christianity.
In biblical tradition, 13 people attended the Last Supper, including Judas, who betrayed Jesus. Judas was said to be the 13th person to take his seat at the table. The next day was the day of Christ’s crucifixion—a Friday (hence the tradition of Good Friday). Christians came to believe that seating 13 people at a dining table was bad luck.
A similar story can be found in Norse mythology.
Legend holds that the trickster god Loki tricked the blind winter god Höd into killing his brother Baldr with a mistletoe-tipped spear at a dinner party. Loki was the 13th guest.
Superstitions spread gradually, and in many cases, people aren’t sure why they follow them—if you traveled back to the Middle Ages and asked someone why the number 13 was unlucky, they probably wouldn’t be able to tell you. However, the Christian and Norse traditions might have played a role.
Throughout history, Friday has also had a bad reputation.
Several texts from the 16th and 17th centuries reference Friday as unfortunate or gloomy. These ideas were still prevalent about 100 years later, as the poet Lord Byron believed Friday to hold bad fortune. Some sailors also avoid embarking on Fridays, and will sometimes go to great lengths to avoid leaving port until the day has passed.
That might supply the most viable theory for why Friday the 13th is particularly unlucky: It combines the unluckiest day of the week with the unluckiest number.
Another explanation: In 1307, the Knights Templar were arrested on Friday, Oct. 13.
King Philip IV of France ordered the arrests, which allowed him to persecute the secret society (and avoid paying them the debts he’d owed them following a war between France and England).
The knights were burned at the stake. According to legend, the order’s Grand Master, Jacques de Molay, cursed his captors with his last words, thus cursing every Friday the 13th from that point forward.
“God knows who is wrong and has sinned,” de Molay reportedly said. “Soon a calamity will occur to those who have condemned us to death.”
This is an exciting theory, but Friday the 13th wasn’t seen as particularly unlucky in popular culture for several centuries afterward.
In 1907, a popular novel helped to spread the belief.
Fittingly titled Friday, the Thirteenth, the book told the story of a Wall Street broker who manipulates the markets, bringing them crashing down on the eponymous date.
Author Thomas William Lawson was actually a stock manipulator, and he intended for his novel to propel Wall Street reforms that would make the marketplace more ethical. He was also extremely superstitious, and he picked the date intentionally to evoke fear in his readers. Friday, the Thirteenth sold well and may have popularized the superstition among Wall Street traders.
An interesting side note: Lawson invested heavily in a schooner named after him, the Thomas W. Lawson. The ship was wrecked off the Isles of Scilly in the early hours of Saturday, Dec. 14, 1907—but Lawson was in Boston at the time, so to him, the boat wrecked on Friday the 13th.
Today, the superstition of Friday the 13th is well known.
The superstition has grown in popularity since Lawson’s time, and the date itself is, of course, unavoidable. Friday the 13th occurs at least once per year, and can occur as many as three times per year. There are two such dates in 2019 and two in 2020, but 2021 and 2022 will have just one occurrence each. If you’re superstitious—or just a little bit stitious—that’s good news.
Christians say that Christ was crucified on Friday the 13. On Friday the 13th the grandmaster Jacques DeMolay, leader of the Templars, was arrested and died and so did the rest of the Templar because of King Philip's jealousy of the Templars rise to power.