BE AFRAID : Phobia; Triskaidekaphobia, Fear of Number 13

Many people are superstitious about the number 13, but for few people its a full-blown phobia called triskaidekaphobia.
Here are some reasons why people are superstitious about the number thirteen:

*Some Christian traditions have it that at the Last supper Judas, the disciple who betrayed Jesus  was the 13th to sit at the table.

*Triskaidekaphobia may have also affected the Vikings—it is believed that Loki in the Norse pantheon was the 13th god. More specifically, Loki was believed to have engineered the murder of Balder, and was the 13th guest to arrive at the funeral. This is perhaps related to the superstition that if thirteen people gather, one of them will die in the following year. Another Norse tradition involves the myth of Norna-gest: when the uninvited norns showed up at his birthday celebration—thus increasing the number of guests from ten to thirteen—the norns cursed the infant by magically binding his lifespan to that of a mystic candle they presented to him.

*Ancient Persians believed the twelve constellations in the Zodiac controlled the months of the year, and each ruled the earth for a thousand years at the end of which the sky and earth collapsed in chaos. Therefore, the thirteenth is identified with chaos and the reason Persians leave their houses to avoid bad luck on the thirteenth day of the Persian calendar, a tradition called Sizdah Bedar