Hearing that it's Friday the 13th always makes me a little nervous. I decided to find out why. According to several sources, the superstition goes back to the year 700 AD! In Christian traditions, the number 13 has been associated with the Last Supper. That night Jesus and the disciples were sharing an important meal with Judas as the 13th guest. (And we know how that turned out.) There's no other compelling evidence that anything bad ever actually occurred on a Friday the 13th. But if you're superstitious (like me), just throw some salt over your shoulder. You'll be fine!