Superstition scholars squabble over the origins of Friday the 13th. Not historically an unlucky day, it was first deemed so in a late 1800s biography ...
Up until the patriarchal revolution, both Fridays and 13s were held in the very highest esteem. Both the day and the number were associated with the Great Goddesses, and therefore, regarded as the sacred essence of luck and good fortune.
the Stress Management Center and Phobia Institute in Asheville, N.C. estimates that 17 to 21 million people in the United States alone are affected by a fear of Friday the 13th.