Image copyright Other Image caption The Thirteen Club's papers kept poking fun at superstition - and may have popularised it by mistake

There are three Friday the Thirteenths this year, and if that worries us, we might have to blame a group who were the sworn enemies of all superstition.

Whatever the reason, since time immemorial many have feared Fridays and thirteens.

But why did the two fears come together to create a superstition with a life of its own, marked throughout the English-speaking world?

Not for any mystical reasons, it seems. "From the astrological point of view there is no need to be concerned about Friday 13th ," says Robert Currey of Equinox Astrology.

Dates and days of the week used to be closely related to planetary movements and phases of the moon in a system dating back to the Babylonians, he says, but that's not the case any more.

Sonia Ducie is a numerology consultant who believes strongly in the innate energy of numbers - 13 is "all to do with transformation and change" she says, and she counts Friday as the fifth day, associated with movement.

"You can see how with those two numbers together, it could be very restless," she says, but adds: "It's down to us; the energy's neutral."

Image copyright ALAMY Image caption Thomas Lawson's book starts the Friday 13th artistic tradition that generated the multi-million dollar film franchise in the 1980s.

Why did the combined superstition arise, then?

In 1907 a book called Friday, the Thirteenth was published, by a stock promoter called Thomas Lawson. It was the inspiration for the Friday 13th mythology which culminated in the lurid film and TV franchises starting in the 1980s.

Lawson's book is a dark fable of Wall Street whose central character ruthlessly engineers booms and busts in the market to work revenge on his enemies, leaving misery and ruin in his wake.

In it he takes advantage of the jitters which the date Friday 13th could be relied on to produce in the market traders.

"Every man on the floor and in the Street as well has his eye on it. Friday, the 13th, would break the best bull market ever under way," one character says.

So in 1907 fear of that date was already an established superstition. A quarter century before, it was not.

The Thirteen Club, a gathering of jolly gents determined to defy all superstitions, first met on 13 September 1881 (a Wednesday) though it was formally organised on Friday, 13 January 1882.

Image copyright NYPL Image caption William Fowler had "a big heart" - but was ruthless when he forced a protesting waiter under a ladder.

They met on the 13th of the month, sat 13 to a table, broke mirrors and spilled salt with exuberance and walked in to dinner under crossed ladders. The club's annual reports carefully noted how many of its members had died, and how many of these passed away within a year of attending a club dinner.

It was founded by Captain William Fowler - of whom it was said that everyone associated him with "good fellowship, a big heart, and simple, unostentatious charity" - at his Knickerbocker Cottage restaurant on Manhattan's Sixth Avenue.

As club marshal he "always gallantly and fearlessly led to the banqueting hall," reported the club's "chief ruler" Daniel Wolff.

The New York Times reported that at the first meeting the 13th diner was late, and Fowler dragooned one of the waiters to make up the unlucky number: "Despite his howls he was… just being shoved through the ladders when the missing guest arrived."

The first target of the club was the fear that if 13 people dined together one would soon die. But a second superstition soon followed.

In April 1882 it adopted a resolution deploring the fact that Friday had "for many centuries past, been considered an unlucky day... on unreasonable grounds" and the club sent a call to the President, state governors and judges to stop picking on Friday as "hanging day" and hold executions on other days too.

Image copyright Other Image caption Fowler's Knickerbocker Cottage was where the Thirteen Club started.

But of a joint Friday 13th superstition there is no sign at the club's foundation. It appeared some time between 1882 and the publication of Lawson's book in 1907.

Could that be the club's own fault?

It took every opportunity of bringing its two prime targets together to ridicule them, the Los Angeles Herald reported in 1895: "Whenever, during the past 13 years Friday has fallen on the 13th of the month this peculiar organisation has never failed to hold a special meeting for rejoicing."

The club prided itself that it had put superstition in the spotlight. Its fame was great: the original 13 members had grown to hundreds by the turn of the century and similar clubs were founded in cities across the States. London's Thirteen Club had been founded by 1894, when a music hall song about it appeared.

"Two of these vulgar superstitions you have combated resolutely and without flinching," club scribe Charles Sotheran wrote to the New York members in 1883, "namely the belief in 13 being an unlucky number, and Friday an unlucky day. You have created a popular sentiment in favour of them both."

Sotheran must have meant "made Fridays and 13 less unpopular", but his sentence is ambiguous and it could just as well have meant "made the superstitions popular". So was it this interpretation which established the superstition in public opinion?

The Thirteen Club's doctrine was "that superstition should be assailed and combated and driven off the earth".

If instead it generated one of the most widespread and persistent superstitions of all, that was an unlucky accident indeed.

Friday the Thirteenth

Image copyright Unknown Image caption The persecution of the Templars began on Friday 13 October, 1307.