A different day, the same date
In English-speaking countries the date feared is Friday the 13th. In Greece, and in the Spanish-speaking world, the unlucky date is Tuesday the 13th. In Spanish the date is martes trece or martes y trece, and in Greek it is simply Tuesday the 13th. The two superstitions share the number thirteen but differ in the weekday, and the difference tells us that the weekday is doing as much work as the number.
As with other number superstitions, these are beliefs held by some people, in some places. They are not facts about the calendar, and many people in these countries treat the date as a joke or ignore it.
The Greek Tuesday
In Greek tradition Tuesday has long had a reputation as a day on which important new ventures should not be started, such as a journey, a wedding or a business. The modern Greek word for Tuesday, Triti, means “third”, the third day of the week counted from Sunday. The link to thirteen appears to be a later layering of the general Tuesday unease onto a date that also carries a reputation for bad luck.
The event most often connected with the day is the fall of Constantinople to the Ottoman army, which happened on Tuesday, 29 May 1453. For Greek speakers this was a profound loss, and it is often cited as the reason Tuesday is remembered as a day of misfortune. The day-of-the-week fact is correct. Whether the memory of 1453 is the origin of the superstition, or a story that was attached to an older belief, is harder to say. A tradition that already regarded Tuesday as a difficult day could have found confirmation in the date, and writers on the subject often present the 1453 link as a popular explanation, not as demonstrated history. Some accounts mention other Tuesday disasters as well, but the details differ and are better treated with caution.
The Spanish martes
In Spanish, the weekday is martes, from the Latin dies Martis, the day of Mars, the Roman god of war. The association with war and bloodshed is the usual explanation offered for Tuesday’s bad name, and it fits the pattern of how the seven-day week took its day names from planetary gods in the Romance languages. A well-known proverb says En martes, ni te cases ni te embarques, “On Tuesday, neither marry nor set sail”. Variants add ni de tu casa te apartes, “nor leave your home”. The version with the date, martes y trece, combines the older Tuesday unease with thirteen.
Italy has a related proverb, which warns against marrying, departing or beginning a task on either Friday or Tuesday, naming Venus and Mars, the planetary rulers behind the two weekday names in Italian. The proverb is often quoted in a rhymed form. That is a reminder that the Mediterranean tradition worried about both days, and that the choice of Friday or Tuesday as the single feared day is a later simplification in each region.
The English Friday
The English superstition about Friday has its own history. Friday has been regarded as an unlucky day for centuries in English-speaking Christian culture, usually explained through the tradition that the Crucifixion took place on a Friday. A late-medieval English writer such as Chaucer refers to Friday as a day of ill fortune in at least one passage, which shows that the idea about Friday was already established long before the specific date was feared.
The combination of Friday with the 13th seems to be later. It is commonly linked to the nineteenth and early twentieth centuries, and a 1907 American novel titled Friday, the Thirteenth is often mentioned as helping to popularise it. The precise route by which the two beliefs, one about a day and one about a number, joined is not well documented. It would be safer to say that Friday the 13th emerges as a recognised phrase over time than to name a single moment.
Comparing the two
Putting the traditions side by side shows a few patterns.
- Day first, number second. In both cases an older unease about a weekday seems to have come first. The 13th then added a second, independent reason for worry, giving a date with a double reputation.
- Religious versus planetary memory. The Friday tradition in English leans on Christian memory, while the Tuesday traditions in Spanish lean on the planetary name of the day. The Greek Tuesday leans on historical memory.
- No single explanation. Each explanation fits some evidence and leaves other evidence unexplained. That is typical of a popular superstition, which often accumulates reasons after the belief is in place.
- The number is shared. The belief about unlucky thirteen exists in many of these regions, which is why both traditions use the same date, but the fear of the number varies. In Italy, for example, thirteen is not generally feared.
A note on the calendar
Because the Gregorian calendar repeats on a cycle, every weekday gets its turn at being the 13th. Every year contains at least one Friday the 13th, and the 13th falls on a Friday a little more often than on any other weekday over the full cycle, a result of how the Gregorian reform arranged the leap years. A Tuesday the 13th happens in many years as well. That means anyone who wishes to avoid either date will meet it often, and the belief in its significance rests on tradition, not on any pattern in events.
The two superstitions are best understood as sibling customs: both use the 13th, and both lean on a day that was already considered awkward. Which day a society chose says more about its religion, its language and its history than about the date itself.