The Mayan Eras.
The zero of the Mayan day count, reached by subtracting 12.9.17.9.4 or 1,799,104 days from the position declared above, is shown to be October 14, 3373 B. C. in the backward projection of the Gregorian calendar. The Gregorian readings are preferable to the Julian because they preserve the actual times in the tropical year, but it is sometimes useful to use the days of the Julian Period which can always be found by adding 489384 to the Mayan number.
Now Mayan history does not reach back to the zero date which must be regarded as a theoretical beginning or Mundane Era. The earliest object with a contemporary date is the Tuxtla Statuette with May 16, 98 B. C. It appears, however, that the really historic beginning of the day count was 7.0.0.0.0, 10 Ahau 18 Zac, August 6, 613 B. C. The calendar of months was probably inaugurated in 580 B. C. when 0 Pop, New Year’s day, coincided with the winter solstice. A third era, 9.0.0.0.0, 8 Ahau 13 Ceh, February 10, 176 A. D., is the one used in the Mayan chronicles.