I would like to add to the discussion on "unlucky 13" (http://www.phrases.org.uk/bulletin_board/3/messages/357.html): Regarding the explanations that date back to biblical times or earlier, Merriam Webster makes an interesting point: "But if written references are any indication, the phenomenon isn't all that old (at least, not among English speakers). Known mention of fear of thirteen in print dates back only to the late 1800s. By circa 1911, however, it was prevalent enough to merit a name, ...'treiskaidekaphobia'." http://www.merriam-webster.com/cgi-bin/mwwodarch.pl?Jan.13.2010 Given this argument (that the phenomenon dates back to only the late 1800s), I am inclined to believe the origin implied by this sentence by Mickey Spillane: "Thirteen steps, and thirteen loops that made the knot in the rope. Were there thirteen thousand volts in the chair too?" (last para of Chapter 3 of 'One Lonely Night'). Here's an elaboration of "[a hangman'!
s] thirteen steps, and thirteen loops":
A hangman seeks to break the neck, not to strangulate and not to severe the head. Strangulation is cruel and prolonged; severing of the head is messy. If there are too many loops in the noose, the friction causes it to tighten slowly resulting in a strangulation; if there are too few loops, the noose tightens rapidly resulting in the severing of the head. The number of steps in the platform is based on the height of the platform. I believe it turned out that given the physical attributes of the rope used and of the condemned prisoners, the hangmen ended up needing 13 loops and 13 steps most of the time.