Why is Friday 13th unlucky?
Might Jesus and his 12 apostles have something to do with it? Discover the medieval history behind triskaidekaphobia – the fear of the number 13 – and why it is considered an unlucky number
Forget the Ides of March and Halloween – for some, a Friday that also happens to be the 13th of the month is scariest and unluckiest day of the year.
The fear of Friday 13th is very real. It's even been given a scientific name, paraskevidekatriaphobia, from the Greek words Paraskeví, meaning Friday, and dekatreís, meaning 13.
But what is it about this day and date combo that has given millions the heebie jeebies. Here's what we know of we know about Friday 13th's hazy history.
When did people start believing Friday 13th was unlucky?
It's believed that this superstition began in the Middle Ages. Some think it's related to the Last Supper, when 13 people were present at the meal before Jesus's crucifixion on Good Friday. Others think it's related to the Knights Templar, who were arrested for heresy on Friday 13 October 1307.
But fear of 13 predates Christianity. The number 13 has been considered unlucky for millenia, and by many different cultures around the world.
Why is the 13th unlucky?
The ancient Romans believed that the number 13 was a bad omen, foretelling ill-fortune and death. The Vikings also hated 13, because in Norse mythology a banquet was held for 12 of the Norse gods during which the trickster god, Loki, appeared uninvited, like the wicked fairy in Sleeping Beauty, and as a result the beloved god Balder died.
The Mayans thought that the 13th 'baktun' (a period equivalent to almost 400 years) would spell the end of the world – however, this came and went in 2012.
For centuries, hosts avoided having 13 people seated around a dining table, convinced that the first person to leave would die within the year. Indeed, 16th-century witch-hunters often tried to claim there had been 13 people at a gathering – proof that the accused were witches in league with the devil.
Why is Friday the 13th unlucky?
Why Friday the 13th is considered especially unlucky isn't entirely clear.
The first written record we have of the number 13 and Friday being unlucky in conjunction only dates to the 19th century, in a biography of Italian composer Gioachino Rossini: "He was surrounded to the last by admiring friends; and if it be true that, like so many Italians, he regarded Fridays as an unlucky day and thirteen as an unlucky number, it is remarkable that on Friday 13th of November he passed away."
Friday the 13th remains one of the most prevalent historical superstitions that we carry on today (alongside that of kissing under the mistletoe).
Many people still choose to stay in bed to reduce the likelihood of accidents, and it's estimated that in the US, as much as $900 million is lost in business each time as a result.