SALT LAKE CITY (ABC4) — It’s a day dreaded by many, particularly the superstitious. Friday the 13th. Considered one of the most unlucky days to fall on the calendar, but how did Friday the 13th earn its uneasy reputation?

It’s a mix between the beliefs that both Friday and the number 13 are unlucky. Pair the two together and you have the recipe for either a disaster or a Jason Voorhees movie.

These days, Fridays are often looked forward to. They are a sign of the weekend and the coming days of relaxation and freedom from work. However, according to a blog post by the Library of Congress, Fridays carries unsettling symbolism. The Library of Congress explains in Europe, there was a belief Jesus was executed on a Friday and according to the Old Testament, Friday was the last day of the creation of the Earth. Because of this, Fridays were thought to be more “suitable for endings, not beginnings.”

The unluckiness of the number 13 also may have Christian roots. The Last Supper was attended by 13 guests, one of whom was Jesus’ betrayer, Judas. An even older root in Norse mythology includes a party of 12 gods before it was crashed by a 13th, Loki, which according to the Library of Congress had “disastrous consequences.”

More modern-day situations also gave backing to the “unlucky 13.” One example is the NASA’s moon mission, Apollo 13. The spacecraft, which launched in 1970, was supposed to land on the moon but about six minutes into the launch, an oxygen tank exploded. The Apollo crew was forced to give up their landing, slingshot around the moon and return to Earth, which they were able to successfully do. NASA even classified the mission as a “successful failure.”

The Encyclopedia Britannica also suggests the number 12 is strongly associated with the heavens, and is considered to be a fortunate number. The number 13 immediately spoiling the prosperous 12 only lent to its reputation of being “unlucky.”

When you pair the unluckiness of Friday and the prosperous spoilings of 13 together, it’s sure to be a bad time.

An old 19th Century French article writing about a count who killed his daughter on a Friday the 13th even wrote “It is always Fridays and the number thirteen that bring bad luck!” Of course, the original was written in French and was translated by the Library of Congress.

The date has long been slandered in pop culture. In a French play titled “Bloqué! Vaudeville en un acte” a character declares “I have never had any luck in my life! I was born on a Friday the 13th,” according to the Library of Congress. Of course too, the widely popular Friday the 13th movie franchise starring slasher-horror film icon Jason Voorhees sees the fictional murderer rise on the cursed day to satiate his bloodlust.

Friday the 13th’s unluckiness doesn’t span worldwide, however, and may be more common in the Western world. For example, in Japan, the number four is largely considered unlucky due to its pronunciation being similar to the word for “death.” Both can be pronounced as “shi,” therefore April 4 is considered to be an unlucky day.

On a note to end, did you know there is a word meaning the fear of Friday the 13th? It’s a complicated one: paraskevidekatriaphobia. It might be easier just to say “Fear of Friday the 13th.”