How Did Friday the 13th Start?

Published on February 17, 2025

by Harriet King

Friday the 13th — a date that stirs up dread, sends people canceling plans, and has even inspired horror films. But how did this seemingly random combination of a weekday and a number come to represent bad luck?

The superstition has a fascinating — and surprisingly tangled — history that mixes religion, mythology, numerology, and modern pop culture. Let’s explore where the fear of Friday the 13th came from, and why it still gives us the chills.

Why Is the Number 13 Considered Unlucky?

Before we tackle Friday, let’s talk about the number itself — 13 has long been viewed with suspicion in many parts of the world.

1. Numerological Oddity

Thirteen throws off the balance of 12 — a number often seen as “perfect.”

Here’s why 12 matters:

12 months in a year, 12 zodiac signs, 12 hours on a clock.
In ancient cultures, 12 symbolized completeness and cosmic order.
13 comes after 12 — it’s irregular, extra, and unpredictable.
This made it feel unlucky or even dangerous in old number lore.

2. Religious Associations

In Christian tradition, 13 guests at a dinner table is a bad omen — just ask the Last Supper.

Why it stuck:

At the Last Supper, Judas Iscariot — the betrayer — was the 13th guest.
Jesus was crucified shortly afterward — on a Friday.
Combining Friday and 13 in folklore created a double whammy of bad luck.
This association spread through Western culture over time.

What’s So Bad About Fridays?

It’s not just the number — Friday has also carried negative baggage historically, especially in religious and maritime circles.

Here’s the background:

In Christianity, Jesus was crucified on a Friday — known as Good Friday.
Some ancient cultures considered Friday unlucky for starting new ventures.
Sailors avoided setting sail on Fridays — considered an unlucky day to begin a voyage.
Even some stockbrokers worry about Friday dips in the market (though that’s more myth than math).

When Did the Superstition Start?

The exact origin is fuzzy, but the fear of Friday the 13th seems to be a relatively recent combination of older beliefs.

Some key moments:

The fear of 13 dates back centuries in Norse and Roman lore.
“Friday the 13th” as a specific phrase wasn’t widely recorded until the 19th century.
In 1907, Thomas Lawson published a novel titled Friday, the Thirteenth — about a stockbroker who uses the superstition to manipulate markets.
The superstition gained massive traction after the 1980 horror film Friday the 13th.

The Backstory of Triskaidekaphobia

“Triskaidekaphobia” is the official name for fear of the number 13, while “paraskevidekatriaphobia” refers specifically to fear of Friday the 13th.

Both reflect how human brains latch onto patterns, symbols, and stories — even when they’re illogical. These phobias aren’t just folklore — some people experience real anxiety, and many buildings skip labeling a 13th floor entirely.

Why It’s So Intriguing

Friday the 13th is like a cultural mirror. It reveals how much we want to believe in fate, how numbers and dates can carry emotional weight, and how myths become part of everyday behavior.

Even people who don’t “believe” in it might hesitate before making big decisions on that day — just in case.

What Most People Don’t Know

Here are a few curious facts about Friday the 13th:

There’s at least one Friday the 13th every year — sometimes up to three.
Some airlines skip row 13, and many hotels don’t have a 13th floor.
In Italy, 17 is the unlucky number — not 13.
Studies show Friday the 13th isn’t actually more dangerous — in fact, some accident rates go down.

Bonus Fact

One of the worst stock market crashes in history happened on a Tuesday — proving bad luck doesn’t follow a calendar.

Takeaway

Friday the 13th may not be cursed, but its staying power says a lot about how we think. Superstitions offer control in uncertain times, turning a simple date into something mystical — or ominous.

So if the calendar shows a 13th landing on a Friday, go ahead and knock on wood. Just don’t blame the date — it’s just another Friday, unless we make it more than that.