The origins of Friday the 13th are not entirely clear, but both Friday and the number 13 have been regarded as unlucky in certain cultures throughout history. The fear of 13 dates back centuries, and many believe it originates from the Code of Hammurabi, which reportedly left out a 13th law from its list of legal rules. In Christianity, there were 13 people at the table at the Last Supper, and Jesus was crucified on a Friday. The combination of Friday and the number 13 is a Victorian invention, and it wasnt until the 19th century that Friday the 13th became synonymous with misfortune. The real Friday the 13th hysteria started in the 20th century, and many date this back to Thomas Lawsons book "Friday, the Thirteenth," which is about a stockbroker who chooses this day to deliberately crash the stock market. The popularity of the "Friday the 13th" movie franchise in the 1980s added to the cultural phenomenon.