GeekDad Puzzle of the Week – Friggatriskaidekaphobia

Reading Time: 1 minute

The Dark Ages, in Europe, were a time of fear. There was the fear of invading armies, the plague, dragons — there was a lot the be afraid of. Some people were superstitious — afraid of things based upon omens or signs that weren’t necessarily related to bad luck.

One specific fear that people still encounter today is Friggatriskaidekaphobia – the fear of a Friday falling on the 13th day of the month.

Sir Max is afraid neither of dragons nor of superstitious dates
Sir Max is afraid neither of dragons nor of superstitious dates

If we consider the Dark Ages as starting on July 31, 476 AD, and ending January 1,1000 AD, how many “Friday the 13th” dates were encountered during the Dark Ages?  For purposes of this puzzle we will use the standard, current month names and day counts, the current rules for “Leap Day” calculations, and will assume that the Julian calendar was in use the entire time.  Per most sources, the last day that the Julian calendar was in use was Wednesday, 02 September 1752 AD — please use that date as an anchor for any and all calendar calculations.

As always, please submit your responses to GeekDad Central for your chance at this week’s $50 ThinkGeek Gift Certificate.  Good luck!

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