Doesn't the Friday the 13th belief come from the murders of the Knights Templars? One of the popes decreed their deaths, sent secret correspondences to all the kingdoms threatening excommunications if the kings & queens didn't kill the Templars on the pre-set time, which was a Friday the 13th. Forgot the details other than that. De Molay was one of those killed. They were all tortured to death, as was the custom at the time.