Nothing quite says “unlucky” like the date on the calendar of Friday the 13th – no matter the month or year in which it falls.

It happened twice in 2017 – and will happen twice again this year.

In a leap year, it is entirely possible that this could be a triple occurrence – as if a leap year needed any more superstition surrounding it!

This is so pervasive a superstition in the west that people have been known to actually avoid scheduling major events in their lives.

Given the common response to what is but a mere number on a calendar – the question begs – why? What is the origin of this superstition and why do we yet today keep it alive and well?

The second question might be more difficult to answer. But its origins are steeped in medieval legend and history – perhaps as mysterious as the group with whom its beginnings are associated.

Let’s begin exploring as early as we can fix a point – ancient times, when we know many cultures held the number 13 to be unlucky or portend an ill omen.

It appears prominently in Norse mythology, for instance. The reasons for this are not exactly clear. But what is apparent is that the number 12 is generally held as a number representing completeness, unity and conclusion.

Therefore, 13 is just one too many, upsetting the natural order as human societies have perceived it.

Christians of course observe Friday as the day of Christ’s crucifixion, so there is perhaps a further medieval European social connection to be made there by combining the day of the week with a monthly date.

This is an obscure reach for an explanation, but certainly with what we know about western medieval culture, there seems a logical point of association.

There is a commonly held notion, however, that the origin of the superstition is actually in the early 14th century, wrapped within the actual historical narrative of the suppression of the Knights Templar by French King Philip IV.

On the 13th of October 1307, King Philip ordered the arrest of many of the knights – a quasi-religious military order that grew quite powerful in influence, as well as wealthy, in the wake of the Crusades.

Many of the Templars, including their last Grand Master, Jacques de Molay, were later burned at the stake.

Their crimes, if any, were greatly embellished or even fabricated. Many at the time thought the men completely innocent.

Within this historical truth remains much mystery and legend that persists even to this day. And to that mystery we must also add the uncertainty of any association with our current superstition about Friday the 13th.

It makes a plausible relation, but again, no direct point of origin can be traced.

Perhaps the most likely explanation is found in a combination of all of the above – the human desire for the completion and harmony of “perfect” numbers, the influence of Christianity upon culture, the deeply entrenched allure of mythology, and yes, even the arrest of the last of the Knights Templar – all contribute to our mistrust of Friday the 13th.

As this demonstrates, sometimes the greatest mystery is not the legend, but its origins. In this case, it’s intriguing to know why we continue to perpetuate it, especially given the lack of agreed explanations.

The next Friday the 13th of 2018 will occur in October – the very same day the Knights Templars were arrested in 1307. Now there’s a perfect day to promote a legend!

Dr. Cheryl White is an Associate Professor History at Louisiana State University, Shreveport. As a weekly contributor for Red River Radio’s Shadow Files segment, she takes listeners through urban legends, extracting facts that may exist to support these tales of ghosts and mysteries. The segment can be heard at 7:45 a.m. every Thursday.