For many Americans, Friday the 13th either conjures up images of unlucky things: a black cat, a broken mirror, walking under a ladder – or horror movies (the “Friday the 13th” franchise includes 2 movies that spanned three decades!). But where did our fear of Friday the 13th come from?


Some historians say it came from the Bible, where every event from Eve’s bite of the apple to the start of the Flood to the building of the Tower of Bable is said to have occurred on Friday the 13th. Others say it stems from Jesus’s last supper, where the 13th guest, Judas, betrayed him.


The number 13 on its own has been considered unlucky for some time – there is even a term for someone who has a fear of the number 13: triskaidekaphobia. For those who fear Friday the 13th specifically, there is another term: paraskevidekatriaphobia. Say either of one of those three times fast.


Events that are deemed unlikely – such as a black cat crossing your path, breaking a mirror, or walking under a ladder aren’t necessarily associated with Friday the 13th. It was the Roman’s who first said that breaking a mirror brought seven years of back luck, and the Egyptians who considered walking under a ladder to be back luck. The bad luck associated with opening an umbrella indoors is thought to have come Victorian England, where the spring mechanism on umbrellas made them unpredictable.


While some may laugh at the idea that someone can be afraid of Friday the 13th, a study done at a Stress Management Center and Phobia Institute in Asheville, North Carolina says that as many as 17 to 21 million people in the U.S. are affected by a fear of Friday the 13th. Many US buildings don’t have a 13th floor, partially due to this fear.


One might wonder – has anything good happened on Friday the 13th? A few years ago, TIME magazine shared five positive things that happened – including President Lyndon B. Johnson signing an executive order to eliminate hiring discrimination based on gender (October 13, 1967) and the day the accordion was patented (January 13, 1854).