Got triskaidekaphobia?

It is such a powerful phenomenon, this combination of date and day of the week that occurs at least once a year (including this Friday) has its own designated phobia, slasher-movie franchise and a Wikipedia page of more than 4,000 words.

The fear of the unluckiness of 13 is called triskaidekaphobia. The aforementioned Wikipedia says the origin may have come about from an ancient Norse myth “about 12 gods having a dinner party in Valhalla. The trickster god Loki, who was not invited, arrived as the 13^th guest. He tricked one god into killing another god at the party, and “the whole earth mourned.”

In Christian mythology, the superstition around the number 13 may to relate to “the story of Jesus' last supper and crucifixion in which there were 13 individuals present in the Upper Room on the 13th of Nisan (the first month of the Jewish New Year) Maundy Thursday, the night before his death on Good Friday,” again quoting Wikipedia.

Another theory suggests the 13 heebie-jeebies has to do with the destruction of the legendary Knights Templar.

The story goes that on Friday, Oct. 13, 1307 (716 years ago this Friday), more than 600 Templars were arrested on the orders of King Phillip of France, who had accused them of black magic, scandalous sex practices and corruption, because he owed them money.

Wikipedia says Friday the 13^th occurs at least once every year. It occurred three times, February, March and November, in 2017, and will occur three times again in 2026. The years 2018, 2019 and 2020 each had two Friday the 13ths. A month has a Friday the 13th if and only if it begins on a Sunday. On average, there is a Friday the 13th once every 212.35 days. Friday the 13ths occurs with an average frequency of 1.7218 per year or about 3,477 times since the year 1 CE.

“Credit for popularizing the Friday the 13th myth often goes to Capt. William Fowler, a noted soldier who rubbed elbows with former presidents and other high-profile people of the late 1800s,” according to a story in livescience.com. “Fowler noticed that the number 13 was woven throughout his life (he went to Public School No. 13 in New York City, for example, and fought in 13 Civil War battles), so he decided to combat the "popular superstition against 13," according to his obituary.

“Fowler started a society called the Thirteen Club, which held its first meeting on Sept. 13, 1881. Guests walked under crossed ladders to a 13-seat table festooned with spilled salt. It was a notable party and repudiation of superstition, but Fowler can't take credit for Friday the 13th, specifically: Sept. 13, 1881, was a Tuesday. (Another account, detailed in a blog by the New York Historical Society, puts that inaugural meeting on a Friday the 13th — Jan. 13, 1882, at 8:13 p.m., in room 13 of Fowler's Knickerbocker Cottage.)”

The History Channel’s website (history.com) cites these tragic events on Friday the 13^th:

• September 1940: The Germans bombed Buckingham Palace during World War II;
• March 1964: Kitty Genovese was murdered outside an apartment building in Queens, New York. It was erroneously reported that 38 witnesses heard or saw the attack but no one reported it in what became known as the bystander effect. Police reports indicate some witnesses tried to report the crime, Wikipedia said. Winston Moseley was convicted of Genovese’s murder. His death sentence was commuted to life in prison.
• November 1970: A cyclone killed more than 300,000 people in Bangladesh.
• September 1996: Rapper Tupac Shakur was shot to death.
• January 2012: A Costa Concordia cruise ship crashed off the coast of Italy, killing 30 people.