It isn’t just doomed teens being chased by a hockey mask-wearing psycho that have come to fear Friday the 13th.

The infamous day has filled people with dread for centuries … possibly millennia.

There are many theories as to why the day has joined black cats and broken mirrors as an icon of bad luck. As with most cultural idiosyncrasies, there is likely a smidgen of truth buried within all of these theories.

“The standard explanation about 13 being an unlucky number supposedly comes from Jesus and the disciples,” explains Tim Miller, a Kansas University professor of religious studies.

“Jesus had 12 disciples, and the 13th member of the crowd was Judas, who betrayed him. Because of that, 13 is the embodiment of evil.”

Miller also traces the Friday component of the superstition back to the same spiritual figure.

“Friday is the day on which Jesus was crucified. For a very long time, Christianity had Friday as a day of sadness – a day of fasting, a day of humiliation. Gradually it got less intense,” Miller says.

But this is just one of the many explanations about the origin of Westerners’ aversion to this day.

Christianity strikes

It’s not just crucifixion-based examples that may have bolstered fear of Friday the 13th. There is theological support for stories that Adam and Eve shared an apple (or whatever the fruit du jour was) on a Friday, and that the Great Flood began on a Friday.

Other historians offer a rival explanation involving older religions being toppled by new ones. Friday was linked to Venus in the Roman calendar and to Freya in Norse mythology. Because these pagan female goddesses represented a threat to patriarchal Christianity, they were maligned.

Similarly, the number 13 was often sacred in goddess-worshipping cultures. (There are 13 months in the pagan lunar calendar, which corresponds to the female menstrual cycle.)

When the solar calendar replaced the lunar, 12 edged out 13, which afterward became a numerical pariah.

Norse dinner

Others trace Western culture’s fixation on 13 to Norse mythology.

Balder the Good, the god of light and joy, was supposedly killed at a banquet by the wicked god Loki as the result of him not being invited to the shindig. He crashed the party and tricked Balder’s blind brother, Hod, into throwing a sprig of mistletoe at Balder’s chest – the only thing fatal to the beloved deity.

The story further fortifies the Judas-oriented concept that sitting down to a meal with 13 people is exceedingly unlucky. It’s a belief shared by cultures such as Hindus and Turks for hundreds of years. It remains pervasive in modern culture. Remember Agatha Christie’s novel “Thirteen at Dinner”?

‘Da Vinci Code’ fallout

Leave it to author Dan Brown of “The Da Vinci Code” fame to help popularize another theory that spawns from medieval Europe.

On Oct. 13, 1307, King Philip IV of France coordinated a mass arrest of the Knights Templar. The order had formed 200 years prior during the Crusades in order to fight the spread of Islam. But it had become so powerful that it was deemed a threat to church and state.

Several thousand Templars were charged with heresy and tortured. None of the charges were ever proven, but hundreds died in captivity or were burned at the stake.

Thereafter, the date became synonymous with bad luck.

British folly

Whether trepidation of Friday the 13th began in merry ole’ England or was simply perpetuated there is up for debate. But the day/date routinely pops up as a symbol of misfortune.

Both have a history of being linked to capital punishment in Britain. Friday was the traditional day for public hangings, and victims had to climb 13 steps en route to the noose.

British sailors were superstitious about setting sail on Fridays. (“A voyage begun on a Friday is sure to be an unfortunate one,” marks a common adage.) Similarly, the sentiment was never to embark with a crew of 13.

A common part of British folklore is that the reluctance of seamen to ship out on Friday reached such proportions that the British Admiralty commissioned a ship in the 1800s called H.M.S. Friday, launched her on a Friday and selected James Friday as captain. On her maiden voyage, she reportedly disappeared into the horizon and no one ever saw the crew again.

More bad luck?

It’s interesting to note that not all cultures view Friday the 13th as a day of bad luck. Tuesday the 13th is considered the most feared in Greece in Spain. The Japanese dislike the numbers 4 and 9 as much as 13. In fact, there are no seats with any of those numbers on Nippon Airways passenger planes. On the flip side, the Chinese and ancient Egyptians considered 13 to be a lucky number.

Although psych wards aren’t exactly overflowing with patients suffering from paraskevidekatriaphobics (the actual medical term for people afflicted with a strong irrational fear of Friday the 13th), it’s one of those benchmark superstitions that everybody acknowledges whether they believe in it or not.

“I don’t see any basis for it in real life,” KU’s Miller says. “In my family, it’s a lucky day because my sister was born on Friday the 13th.”