THUNDER BAY – LIVING – “Friday the 13th” is considered unlucky mostly in Western popular culture, but the exact origin is not settled. The best-supported explanation is that it grew out of two older ideas that were later fused together: Friday as an unlucky day in some Christian traditions, and 13 as an unlucky number in parts of European folklore. Researchers at the Library of Congress say the specific superstition is not ancient in its modern form; the earliest clear references they found are in French works from 1834, and by the mid-1800s the idea was common in France before spreading to America.
Why Friday? One traditional explanation is Christian: Jesus was crucified on a Friday, and later folklore also attached other biblical misfortunes to that day. Why 13? A common explanation points to the Last Supper, where 13 people were present before the crucifixion, and to older European stories such as the Norse tale of Loki arriving as a disruptive 13th guest at a banquet. These are part of the folklore around the number, but scholars caution that they are explanations people tell about the superstition, not a single proven point of origin.
A lot of people also connect the date to the arrest of the Knights Templar on Friday, Oct. 13, 1307. That event really happened, but it is better understood as a later story attached to the superstition than as a confirmed origin. The Library of Congress notes that the Templar theory is often suggested, yet the documentary evidence points more strongly to the superstition taking shape in 19th-century France.
The idea got a big boost from modern culture. A 1907 novel titled Friday the 13th shows the belief was already familiar to readers, and the 1980 horror film franchise made the date feel even more ominous. In other words, folklore created the superstition, and pop culture helped keep it alive.
Other similar superstitions fall into two groups. One is “bad-luck dates and numbers”: in Spain and Greece, Tuesday the 13th is often considered unlucky; in Italy, Friday the 17th is feared; and in China and Japan, the number 4 is widely avoided because it sounds like the word for “death.” Interestingly, 13 is not unlucky everywhere: Smithsonian Folklife notes it can even be lucky in some Chinese contexts.
The other group is everyday omens: black cats crossing your path, walking under a ladder, opening an umbrella indoors, breaking a mirror, or spilling salt. Britannica specifically lists these as superstitions akin to Friday the 13th.
So the reason people think Friday the 13th is bad luck is less “one historical event made it cursed” and more “older fears about Friday and 13 gradually merged, then literature and movies made the idea memorable.” There is folklore behind it, but no evidence the date is actually more dangerous than any other.
