As another Friday the 13th rolls around, the Twitterverse is wondering: Why, exactly, is that date considered unlucky?
In numerology, 12 is considered the number of completeness: 12 months in the year, 12 hours of the clock, etcetera. Thirteen, on the other hand, is seen as irregular. And Friday, despite being masterfully celebrated in song by Rebecca Black, was named for the Norse fertility goddess Frigga, who was later branded as a witch by the Christians. The story goes that Frigga would get together on Fridays with 11 other witches plus the devil—13 in all—to plot evil twists for the coming week.
Another theory has to do with the Knights Templar, who protected Christian pilgrims during the Crusades but who were rounded up and falsely accused of heresy on, you guessed it, Friday the 13th in the year 1307.