Friday the 13th may be one of the most firmly rooted American superstitions -- along with black cats and walking under ladders. But where did the superstition originate?
Some believe the discomfort surrounding the number 13 dates back to Jesus' last supper with the 13th guest being Judas who betrayed him.
Fear of the number 13 -- a condition also known as triskaidekaphobia -- may even predate Jesus, though. One Norse myth tells the story of 12 gods who were having a dinner party at Valhalla, heaven in Norse mythology. A 13th guest arrived -- the mischievous god Loki who got the blind god of darkness, Hoder, to shoot and kill god of joy Balder with a mistletoe-tipped arrow.
Folklore historian Donald Dossey told the National Geographic that the fear of Friday the 13th has a real impact in people's decision-making and can even affect the economy. "It's been estimated that $800 or $900 million is lost in business on this day," Dossey said, "because people will not fly or do business they would normally do."
Friday the 13th is not universally a day of ill omen, however. In some Spanish-speaking countries the unlucky day is Tuesday the 13. Martes, or Tuesday, in Spanish derives from Mars, the god of war, and thus connotes death.
Shaman and ritual expert Donna Henes offers another explanation for Friday the 13th, rooted in goddess traditions. "Thirteen is certainly the most essentially female number -- the average number of menstrual cycles in a year," Henes writes in a HuffPost blog. "Thirteen is the number of blood, fertility, and lunar potency. 13 is the lucky number of the Great Goddess."
Henes explores the day's significance in several traditions around the world:
Representing as it does, the number of revolutions the moon makes around the earth in a year, 13 was the number of regeneration for pre-Columbian Mexicans. In ancient Israel, 13 was a sanctified number. Thirteen items were decreed necessary for the tabernacle. At 13 years of age, a boy was (and still is) initiated into the adult Jewish community. In Wicca, the pagan goddess tradition of Old Europe, communicants convene in covens of 13 participants. Thirteen was also auspicious for the Egyptians, who believed that life has 13 stages, the last of which is death -- the transition to eternal life.
Held holy in honor of Shekinah, the female aspect of God, Friday was observed as the day of Her special celebrations. Jews around the world still begin the observance of the Sabbath at sunset on Friday evenings when they invite in the Sabbath Bride. Friday is the Sabbath in the Islamic world. Friday is sacred to Oshun, the Yoruba orisha of opulent sensuality and overwhelming femininity, and also to Frig, the Norse Goddess of love and sex, of fertility and creativity. Her name became the Anglo-Saxon noun for love, and in the 16th century, frig came to mean "to copulate."
Friday was associated with the early Mother Creation Goddesses for whom that day was named. In Anglo-Saxon, Scandinavian, Icelandic, and Teutonic cultures She was called variously, Freya, Freia, Freyja, Fir, Frea and Frig. Friday is Frig's Day, Frigedaeg, in Old English, Fredag in Danish, Freitag in Dutch. In Mediterranean lands, She reigned as Venus. In Latin, Friday is the Day of Venus, Dies Veneris; Vendredi in French, Venerdi in Italian and Viernes in Spanish.
For these reasons, Henes said, Friday the 13th should be a day of celebration in honor of "Lady Luck" -- superstition be damned.