In American culture, Friday the 13th is a notorious day...but do we know why? Like any legendary day...how the date became infamous is a little hard to track down.
First, let's dive a little into 13. Like 666, 13 also seems to be a number mired in bad luck ad mystery. In fact, according to refinery29, 13 has "countless malevolent origins." Ancient Norse Lore holds that " evil and turmoil were first introduced in the world by the appearance of the treacherous and mischievous god Loki at a dinner party in Valhalla. He was the 13th guest, upsetting the balance of the 12 gods already in attendance." Notably, Judas was the 13th guest at the last supper. It should also be noted that 13 only seems to be a concern in the Western world (in places like ancient Egypt, 13 is lucky and other numbers are evil...like 4 in much of Asia). Finally, in the ancient world 12 was considered a "perfect number." This can be seen today - calendars with 12 months, a day is 2 parts of 12 hours, etc. Because 13 follows this perfect number, it is "found lacking and unusual."
Now that we know a little bit about 13...let's dive deeper into the lore surrounding Friday the 13th. We've established 13 isn't a number held in the highest esteem, likewise neither was Friday. In fact, the literature from the middle ages often linked Friday to meager harvests, bad business, and disastrous travel. Even in the perennial Canterbury Tales by Geoffrey Chaucer made sure to note, "And on a Friday fell all this mischance."
So, is Friday the 13th simply the marriage of two unlucky/evil/mysterious things? Maybe, but maybe not. The fear of Friday the 13th is so significant it has a name - paraskevidekatriaphobia. You can also see the effects of it in elevators - although not every building skips a "13" button on the elevator, you may notice that several do...especially older buildings.
Others believe it has a religious origin. As mentioned above, there were 13 guests at Jesus' last supper the night before his death on Good Friday.
Others believe that popular culture is to blame. For example, Thomas W. Lawson's popular novel Friday, the Thirteenth published in 1907. In the book, a man takes advantage of the superstition of Friday the 13th to create a Wall Street panic.
In more recent times, movies like the Friday the 13th have further popularized and, in a way, normalized the unluckiness and noterity of Friday the 13th.
Snopes has several interesting anecdotes and pull quotes from different historical sources that seem to support that Friday the 13th isn't at the luckiest of days. You can read through them by clicking the third "link" at the top of the page!
In 2018, Friday the 13th will fall on April 13 and July 13.
The above image is liscensed under Attribution 2.0 Generic (CC BY 2.0)
and is from Flickr user Frédéric BISSON