Even though this theory is in dispute, the story is intriguing.

One of the most popular theories, however, links Friday the 13th with the fall of a fearsome group of legendary warriors—the Knights Templar. Founded around 1118 as a monastic military order devoted to the protection of pilgrims traveling to the Holy Land following the Christian capture of Jerusalem during the First Crusade, the Knights Templar quickly became one of the richest and most influential groups of the Middle Ages, thanks to lavish donations from the crowned heads of Europe, eager to curry favor with the fierce Knights. By the turn of the 14th century, the Templars had established a system of castles, churches and banks throughout Western Europe. And it was this astonishing wealth that would lead to their downfall. For the Templars, that end began in the early morning hours of Friday, October 13, 1307.