If 13 people sit down to dinner together, one will die within the year. The Turks so disliked the number 13 that it was practically expunged from their vocabulary (Brewer, 1894). Many cities do not have a 13th Street or a 13th Avenue. Many buildings don’t have a 13th floor. If you have 13 letters in your name, you will have the devil’s luck (Jack the Ripper, Charles Manson, Jeffrey Dahmer, Theodore Bundy and Albert De Salvo all have 13 letters in their names). There are 13 witches in a coven. Never change your bed on Friday; it will bring bad dreams. Don’t start a trip on Friday or you will have misfortune. If you cut your nails on Friday, you cut them for sorrow. Ships that set sail on a Friday will have bad luck – as in the tale of H.M.S. Friday … One hundred years ago, the British government sought to quell once and for all the widespread superstition among seamen that setting sail on Fridays was unlucky. A special ship was commissioned, named “H.M.S. Friday.” They laid her keel on a Friday, launched her on a Friday, selected her crew on a Friday and hired a man named Jim Friday to be her captain. To top it off, H.M.S. Friday embarked on her maiden voyage on a Friday, and was never seen or heard from again.
The name “Friday” was derived from a Norse deity worshipped on the sixth day, known either as Frigg (goddess of marriage and fertility), or Freya (goddess of sex and fertility), or both, the two figures having become intertwined in the handing down of myths over time (the etymology of “Friday” has been given both ways). Frigg/Freya corresponded to Venus, the goddess of love of the Romans, who named the sixth day of the week in her honor “dies Veneris.”
Friday was actually considered quite lucky by pre-Christian Teutonic peoples, we are told — especially as a day to get married — because of its traditional association with love and fertility. All that changed when Christianity came along. The goddess of the sixth day — most likely Freya in this context, given that the cat was her sacred animal — was recast in post-pagan folklore as a witch, and her day became associated with evil doings.
Various legends developed in that vein, but one is of particular interest: As the story goes, the witches of the north used to observe their sabbath by gathering in a cemetery in the dark of the moon. On one such occasion the Friday goddess, Freya herself, came down from her sanctuary in the mountaintops and appeared before the group, who numbered only 12 at the time, and gave them one of her cats, after which the witches’ coven — and, by “tradition,” every properly-formed coven since — comprised exactly 13.And Loki makes thirteen. . .
Twelve gods were invited to a banquet at Valhalla. Loki, the Evil One, god of mischief, had been left off the guest list but crashed the party, bringing the total number of attendees to 13. True to character, Loki raised hell by inciting Hod, the blind god of winter, to attack Balder the Good, who was a favorite of the gods. Hod took a spear of mistletoe offered by Loki and obediently hurled it at Balder, killing him instantly. All Valhalla grieved. And although one might take the moral of this story to be “Beware of uninvited guests bearing mistletoe,” the Norse themselves apparently concluded that 13 people at a dinner party is just plain bad luck.