The origins of the superstition surrounding Friday the 13th are not entirely clear, but there are several theories. One theory is that the fear of the number 13 dates back to the Bible, where Judas, who betrayed Jesus, was the 13th guest at the Last Supper, which was held on a Thursday. The next day, Friday, was the day of Jesus crucifixion, which may have contributed to the negative connotation of the day. Another theory is that the combination of Friday and the number 13 is a Victorian invention that became synonymous with misfortune in the 19th century.

It wasnt until the 20th century that Friday the 13th became a cultural phenomenon, with the publication of Thomas W. Lawsons novel "Friday, the Thirteenth," which is about a stockbroker who deliberately crashes the stock market on that day. The popularity of the "Friday the 13th" movie franchise in the 1980s also contributed to the superstition.

In summary, the origins of Friday the 13th are not entirely clear, but the superstition surrounding the day likely has roots in both Christian tradition and Victorian-era culture.