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 A Note on the 365-day Calendar Number-Name for the Year:

     In addition to the number-names for each day within the 365-day calendar, the Mesoamerican priests chose a system to give each 365-day year within the 52-year calendar round a specific number-name. Each specific number-name was unique within the 52-year calendar round. The number-name of each new year was correlated with either the first day of the year or the last day. In order to establish this naming system, the priests established two separate "gears" patterned after the 260-day calendar year. That is, they overlaid the 260-day year and its day names and numbers on top of the 365-day calendar framework.

     The first "gear" was patterned after the day names in the 260-day calendar (see illustration). In other words, the cycle of 20 named days from the 260-day calendar would continually rotate through the year of 365 days. The number 365 cannot be evenly divided by 20; however, 20 will go into 360 exactly 13 times. This leaves 5 extra days every year. What this means is that in the rotation of these day names through the 365-day calendar, the name for New Year's day (or the last day of the year) would be bumped forward 5 spots on the list each year. In other words, suppose the first year in the 52-year calendar round started with the first day name on the 20 day list, which is "Crocodile." The next year the name would be bumped forward five spots to day name #6 (or "Death"). The next year the name would be bumped forward another five spots to day name #11 (or "Monkey"). The next year the name would be bumped forward another five spots to day name #16 (or "Vulture"). The next year would bring us back to day name #1 again. Thus for those calendars starting (or ending) with day name #1, they would also have day names #6, #11, and #16 in their cycle. This cycle has been termed "Type I."

     A "Type II" cycle would be for those calendar years starting with day name #2. It would also involve day names #7, #12, and #17.

     Type III = #3, #8, #13, and #18.

     Type IV = #4, #9, #14, #19.

     Type V = #5, #10, #15, and #20.

     As one can see, there are only five cycle types, and only four names per type.

 

     The other "gear" for giving a specific number-name within the 52-year calendar round was patterned after the 13-day cycle. Each day in that cycle was given a number (1-13). Correlating this "gear" with the 365-day calendar, one can see that the number 365 cannot be divided by 13 evenly. The number 13 goes into the number 364 exactly 28 times. This leaves 1 extra day every year. What this means is that in the rotation of these 13 numbered days through the 365-day calendar, the number for New Year's day (and thus the number for the specific year name) would be bumped forward 1 number every year.

     In summary, by combining the workings of these two "gears," the priests had 52 specific number-names by which to call their years. For any "type" of calendar name cycle, there were 4 names. There were also 13 number choices. 4 times 13 = 52, which means that within a 52-year calendar round, each year had a unique number-name.