The number 13 is well known as being unlucky. Friday the 13th is especially known as an unlucky or even dangerous day among those who hold to superstition. But why is this day seen in such a negative light? And why is even the number “13” seen as unlucky on its own? It seems that this superstition springs from Christianity, but even more-so from Christian anti-Pagan sentiment.
Roughly 8% of the US population subscribes to the belief that Friday the 13th is inherently an unlucky day. There is an official word for the fear of Friday the 13th, which is sort of scary itself: Paraskevidekatriaphobia. Which, while looking like absolute nonsense, is actually just a combination of the Greek word for Friday, which is “Paraskevi,” and the word used to describe the fear of the number 13, “Triskaidekaphobia.” So while it looks crazy, the word does make sense.
The most likely source of the negative superstitions surrounding Friday the 13th is Christianity. Of the many, but generally incomplete sources on the subject, all agree that the unlucky association with the number 13 likely stems from the story of the Last Supper. It is said that at the Last Supper, Jesus Christ was accompanied by his 12 apostles, making the total number of the dinner party 13 members. Judas Iscariot is believed to have been the 13th guest to arrive. Judas is recognized as the man who betrayed Jesus and revealed his identity to those who would later imprison and execute him. Because the 13th place at the table was occupied by the great betrayer Judas, that the number became associated with ill fortune and deceit.
It is possible that detest toward Pagan beliefs and goddess worship among Christians also influenced the belief that the number 13 is cursed. The original calendar that was followed by pre-Christian societies had 13 months to correspond with the 13 full moons that occur throughout the year. The moon has historically been associated with the mother goddesses and feminine power, partially due to the presumed relationship between lunar cycles and menstruation. The Gregorian calendar removes this 13th month and bases the counting of days around only 12. It is likely that Christians of the time were opposed to the way that 13 reflected worship of the moon, of women, and of goddesses.
Friday has also been a notorious day within Christian theology, as many different catastrophic events are believed to have taken place on Fridays. It is unclear if this has always been the case, or if this developed later, when Christian leadership began to associate Fridays with heathen worship. This association arose due to Friday being named after the Norse Goddess Frigg. The Old English word for the day was Frīġedæġ, which means “Frigg’s Day,” or “Day of Frigg.” Frigga is Odin’s wife, and queen of the Aesir gods in Norse mythology. As such, she is held in very high regard among those who follow Norse Pagan spirituality. It is believed that when Christianity became the dominant European belief system, it was agreed that having a day associated with the worship of a mother goddess was unacceptable, and even inviting a curse upon the people. The church actively demonized Frigg, referring to her as a witch of the devil, or as an evil figure. It is possible that this idea is what caused Christianity to allocate so many bad events to having occurred on Fridays, such as the death of Jesus, the Great Flood, and the eating of the forbidden fruit by Adam and Eve.
Some popular sources have claimed that the number 13 was also seen as negative within Norse mythology, but the commonly cited instance in the sagas is always described incorrectly. While researching this article, I found several sources suggesting that Odin’s son Baldur was killed due to Loki’s manipulation at a dinner party with 13 gods present. According to the Eddas however, Baldur’s death occurred while the gods were together playing in the woods, shooting arrows at Baldur and laughing because he couldn’t be killed by normal means. This misunderstanding seems to spring from people mixing this story up with the Christian story of the Last Supper.
For those who have Paraskevidekatriaphobia, the day seems more unlucky than others. This is due to confirmation bias which makes people notice things more when they are expecting them. If someone believes that something is true, they will unconsciously take note of every detail that adds evidence to that belief. This is a phenomenon that occurs constantly and in reference to almost everything in life, and no person is really immune to its effects.
Today, Friday the 13th is actually a measurably more safe day to travel and go about your business. This is because while only 8% of the US population truly believes that the day is unlucky, the superstition is well recognized by just about everyone. Knowing that it’s considered an unlucky day does influence peoples’ decisions about traveling and engaging in various activities, even if just a little, resulting in fewer collisions on the road, fewer person-to-person interactions which can lead to altercations, and fewer accidents in general.