17 Superstitions You Didn't Know Were Rooted In History

Black cats are important figures in many cultures, but they're not always bad luck. In ancient Egyptian culture, cats of any color were held in high esteem, so seeing one cross your path was actually a good thing. According to Live Science, that belief popped up again in the 17th century, when King Charles I of England kept a beloved black cat as a pet. Apparently, he loved it so much that when it died, he claimed that his luck had passed away with it. Ironically, he was arrested the next day and eventually beheaded.

Combine this with medieval beliefs that black cats were demonic companions to witches, and you have all the ingredients for a superstition that persists today.

The Superstition: Watch out for construction sites and housework. If you're unfortunate enough to walk under a ladder, you'll be cursed with bad luck unless you walk backwards under the ladder again.

Aside from being literally dangerous — what if something falls on your head? — walking under a ladder is considered bad luck for largely symbolic reasons. Early Christians believed that the number three was sacred for its connection to the Holy Trinity, and by extension, so was the triangle. When a ladder leans up against a wall, it forms that very shape, and walking underneath it "breaks" the Trinity. Not only was this blasphemous, but it might also attract the Devil himself.

Other historians have pointed out that a leaning ladder resembles the gallows, which use ladders so the person being hung can climb high enough to reach the noose. Either way, ladders have some not-so-great connotations.

The Superstition: Every month, hospitals experience an influx of patients. Criminals get more aggressive. Maybe you even find yourself more irritable than normal — and it's all thanks to the full moon's influence.

The association between the moon and madness has been around long enough to influence the English language: "lunacy" and "lunatic" are both derived from the Roman goddess of the moon. In the 5th century B.C., the ancient Greek physician Hippocrates attributed mania to a visitation from Selene (the Greek equivalent of Luna), writing that "one who is seized with terror, fright and madness during the night is being visited by the goddess of the moon." Thousands of years later, many medical workers still believe the full moon brings chaos.

If you see a heads-up penny on the ground, pick it up for good luck. If it's lying tails-up, turn it over for the next person to come along. There's even a chant to remind you of the superstition: "Find a penny, pick it up. All day long, you'll have good luck."

Obviously, hoarding enough pennies will bring material wealth, but some historians believe the superstition has origins dating back to the Middle Ages. Back then, the chant was about picking up pins rather than pennies. At the time, pins were surprisingly expensive, so coming across a random pin really was a stroke of good fortune. Pins eventually became cheaper, and pennies replaced them in the nursery rhyme.

A rabbit's foot can be carried around for good luck. Depending on who you ask, the charm might be useless unless it's the left hind foot, preferably taken from an animal killed or captured in a cemetery. You know, because carrying around part of a dead animal wasn't already gross enough.

The origins of this belief appear to be twofold. According to Celtic beliefs, rabbits were lucky animals. They had to be — rabbits live in burrows underground, putting them so close to the gods of the underworld they must have some sort of special protective powers. Therefore, carrying around part of a rabbit was thought to protect against bad spirits.

Fast forward several thousand years, and a similar belief showed up in the American South. It's not clear whether the tradition was influenced by Celtic beliefs or not, but either way, rabbit feet are commonly used in hoodoo, a traditional African American folk spirituality. Furthermore, Br'er Rabbit is a clever, courageous figure in African and Southern American folklore. It's easy to see why carrying around part of a rabbit would become associated with luck, and over time, this belief spread out of the South.

If you break a mirror, you don't just have to fork over the money for a new one. You'd better stock up on rabbit feet, because a simple act of clumsiness has cursed you to seven years of catastrophe. Well, unless you throw salt over your shoulder, spin around three times counter-clockwise, or any of the other prescribed remedies for bad luck.

You've probably heard that in many ancient cultures, your reflection was seen as a representation of your soul, so damaging a mirror also damages your self. The bit about bad luck lasting for seven years comes from the early Roman belief that your body regenerates every seven years — if breaking a mirror signifies a break in your soul, you're stuck with the resulting bad luck for seven years until your soul grows back.

There's a more worldly aspect to the belief as well: When glass mirrors with silver coating were first manufactured in the Renaissance, they were exorbitantly expensive. If you broke one, your best chance of paying the owner back was to be their indentured servant... for seven years.

Known as the Number of the Beast, the number 666 is associated with Satan in Christian tradition. Accordingly, it's seen as an omen of bad luck, to the point where Ronald Reagan changed his street address from 666 to 668 after moving out of the White House.

Fear of the number 666 is based on passages in the final book of the Bible, but according to Biblical scholars, the "beast" in Revelations doesn't actually refer to Satan. Instead, it's used to denote Rome, Roman emperors, and Roman forms of worship at a few different points in the book.

This has led some anthropologists to believe that the author of the text was actually referring to Emperor Nero; when the Greek spelling of "Nero Caesar" is translated to Hebrew, the letters add up numerically to 666.

Every Thanksgiving, families put off the inevitable post-dinner nap long enough to watch two people snap a wishbone in half. Whoever ends up with the bigger piece gets to make a wish, while the other just has a piece of turkey clavicle to treasure forever. Fun?

Despite what you might think, this Thanksgiving tradition didn't come from the Pilgrims — at least, not directly. It came from English culture, which was borrowing from Roman culture, which was borrowing from Etruscan culture.

Located in modern-day Italy, the Etruscans were really into poultry. Believing that birds could predict the future, they set the wishbone out to dry every time they slaughtered a chicken, hoping to take advantage of the bird's oracular powers even after it was dead. When people walked by, they would stroke this magical bone and make a wish. The Romans later adopted this tradition and added the bit about snapping the bone in half, and eventually, it made its way aboard the Mayflower to the Americas.

You're about to ask someone out, or you're flying standby and hoping you made it on a plane home. Whatever the reason, you need some luck — not a lot, but enough so that you cross your fingers to make sure your wish comes true.

The cross is a powerful religious symbol, even outside of Christianity. As Refinery29 points out, people used to wish on the mid-point of the cross, where its powers were supposed to be strongest, to ward off evil that would get in the way of their wish. Over time, that evolved and it became customary for two people to cross their fingers for good luck, then it morphed again into a single gesture. It's also possible that crossed fingers were used as a way to identify other Christians before the religion was legalized in its early days, so it was fortunate to come across one of your brethren.

You're cooking up a storm when something makes you jump (or maybe you're just clumsy) and you knock over a container of salt. Without really thinking, you toss a pinch of salt over your left shoulder before the bad luck catches up to you and continue making dinner. Like so many things on this list, spilled salt is a sign of bad luck.

The most obvious explanation for the superstition surrounding salt is that before it was considered bad luck, it was simply impolite. Thousands of years ago, salt was expensive enough to be used as currency at times; Roman soldiers, for example, were paid in the spice. (That's where the word "salary" comes from.) Therefore, spilling salt meant bad luck because essentially, you just scattered grains of money everywhere. Over time, it's possible this evolved into the belief that it brings misfortune.

There are also a few connections with Christianity. First, in Leonardo da Vinci's depiction of the Last Supper, the disciple who betrayed Jesus is shown spilling the salt — possibly an omen of misfortune to come. Second, the bit about the left shoulder appears to come the early Christian belief that good spirits hung around your right shoulder, while the Devil lurked off to your left. If you invite bad luck by spilling salt, you can avert it by tossing the salt right in Satan's face if you're fast enough.

Horseshoes have been associated with good luck for centuries. Even today, it's not uncommon to see them hanging above a building entrance, although there's considerable debate about which way best utilizes the symbol's powers. In some parts of the world, hanging it upside down lets the good luck fall out; in others, the position lets the good luck shower down on the building's occupants.

Many centuries ago, northern European folklore held that fairies lived among people. Some were relatively harmless, but the troublemakers were blamed for failed crops, childbirths gone wrong, and the like. Luckily, fairies could be warded off with iron, so people hung horseshoes above their doorways to keep the fair folk from getting inside. As Live Science points out, some folklorists believe that horseshoes had the added benefit of resembling the moon god's crescent, scaring off the fairies and warding off the evil eye. During the Middle Ages several hundred years later, it was believed that witches were afraid of horses and iron. Anyone dabbling in the occult would be unable to enter a home where a horseshoe hung over the door.

There's also a specific figure associated with the horseshoe: Saint Dunstan, the patron saint of blacksmiths who became the Archbishop of Canterbury in 959 A.D. According to legend, he tricked the Devil into allowing Dunstan to shoe his cloven hoof with a horseshoe. Before taking the iron off, Dunstan asked the Devil to promise never to enter a house with a horseshoe above the door, and the Devil agreed.

The second you step indoors during a rainstorm, you'd better close your umbrella as quickly as possible. Otherwise, bad luck will "rain" down on you.

Historians don't agree on precisely when the superstition about opening an umbrella indoors came about. Some point to ancient Egyptian times, when umbrellas made of papyrus and peacock feathers served as protection from the sun. Supposedly, opening on inside or in the shade was a direct offense to the sun god himself.

Others believe the superstition is far more recent. In the Victorian era, umbrellas as we know them were a new invention, and there were still several kinks to work out — namely, the force with which they sprung open. Umbrellas were so rigid that they could seriously injure someone, making them literally dangerous to open indoors.

The number 13 is bad news. Many Western buildings will avoid labeling a 13th floor, and it's unlucky to have 13 guests at a dinner party. Don't even think about getting married on the 13th day of any month, especially if that date falls on a Friday.

According to historians, the fear of the number 13 might date back thousands of years. Ancient Sumerians, for example, believed that 12 was the perfect number; its neighbor, 13, just couldn't stand up to the comparison.

There are also several myths about the undesirable 13th guest. In Nordic folklore, for example, chaos was introduced to the world at a divine dinner party when Loki, the god of mischief, showed up and became the 13th member of the party. In the Bible, Judas Iscariot was the 13th person to arrive at the Last Supper after betraying Jesus. Over time, all this may have combined to create the superstition that continues today.

Whenever you voice something optimistic, find the nearest wood and knock on it with your knuckles. Otherwise, you'll find yourself disappointed when your wish doesn't come to pass.

Knocking on wood is one of the most common superstitions in the country it's far older than the U.S. In pagan religions, trees were considered sacred, so it's likely that worshipers used to lay their hands on the nearest wood to ask the spirits living inside it for a favor. Later, it was common in some European cultures to make a bunch of noise to chase away evil spirits in their houses and trees — or to keep the spirits from overhearing an optimistic statement and making sure it didn't happen. Over time, this tradition may have evolved into simply knocking on wood.

If you live in an English-speaking country, it's probably automatic at this point: Whenever someone sneezes in your hearing, you bless them and return to whatever you were doing.

You've probably heard that back in the day, people used to believe that sneezes separated the soul from the body. Blessing them was a quick way to make sure the Devil didn't get a hold of someone's soul while it was floating around.

But there’s another aspect to the ritual that’s less well-known. In the sixth century, the bubonic plague was spreading through Italy. The most recognizable symptom? Severe attacks of sneezing, quickly followed by death. In case someone died before they could be blessed by a member of the clergy, Pope Gregory I supposedly ordered followers to say “God bless you!” whenever someone sneezed.

Certain bodies of water have magical properties. Toss a coin into a fountain or a well, and you'll find that your wish might come true.

Historically, clean water wasn't exactly easy to come across. Many early European cultures believed that sources of potable water, like wells and fountains, were gifts from the gods — and places where they hung out. To appease them, thank them, or ask the gods for a favor, it became customary to toss a coin into a source of clean water, and the concept of the wishing well was born.

One particularly famous wishing well is pictured here: Coventina's Well in Northampton, England. The minor goddess of childbirth and healing is said to reside in the well, which is the source of a spring. Researchers have found coins, buttons, and other trinkets inside the well dating back to the fifth century.

Commonly seen on St. Patrick's Day, four-leaf clovers are one of the oldest signs of good luck in Western tradition. We give them out to newlyweds, and finding one by chance is a sign of good things to come.

Obviously, one reason four-leaf clovers are considered lucky probably stems from their rarity; more often than not, clovers have three leaves. In early Irish tradition, however, the plant was also common in Druid rituals, from healing the sick to warding off evil. Over time, the four leaves of a clover have come to represent different qualities: hope, faith, love, and luck.

The good news? Four-leaf clovers might be rare, but they're not impossible to find. According to some estimates, your chances of finding one are about one in 10,000. Good luck!