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Module 3 of 6

The Count of Days: Twenty Signs, Thirteen Numbers

The engine of the system. Twenty day signs turn against the numbers 1 through 13, producing 260 unique days, thirteen-day trecenas, and the sequence recorded in the codices.

Lecture

What to take from this module

  • 20 signs × 13 numbers = 260 days before any pairing repeats. Nothing is arbitrary about the length.
  • Each block of thirteen days (a trecena) takes its character from the day sign that opens it; the number gives the strength of that influence.
  • The codices — Borgia, Borbonicus, Telleriano-Remensis — are working documents of this count, not decoration.
  • Day signs carry patrons and auguries; day keepers read them as testimony about the character of a day.

Terms introduced

Trecena
A run of thirteen days named for its opening day, e.g. 1 Kiawitl.
Day sign
One of the twenty: Zipaktli, Ehekatl, Kalli, Kwetzpallin, Koatl, Mikiztli, Mazatl, Tochtli, Atl, Itzkwintli, Ozomahtli, Malinalli, Akatl, Ozelotl, Kwawhtli, Kozkakwawhtli, Ollin, Tekpatl, Kiawitl, Xochitl.

Supplemental videos

The Teotihuacan Fire Ceremony | Native America | PBS

Handout

PDF · printable

Handout: The Twenty Day Signs & Counting to Twenty in Nawatl (PDF)

Printable reference with all twenty day signs and their meanings, the Nawatl numbers 1–20, a ten-question quiz and a full answer key.

PNG · 300 dpi page images

Print-resolution renders of every page, for slides, screens or reprinting.

Page 1Page 2Page 3Page 4

Additional readings

Finish the readings and supplemental videos before moving to the next module.

Checkpoint

  1. Write out the next five days after 10 Tochtli.
  2. How many days pass before the same sign and number meet again?

Cumulative exam · 13 questions

Module 3 exam

This exam covers Module 3 and everything before it. You need more than 90% correct to pass.

  1. 1.Mesoamerican timekeeping is best described as:(Module 1 review)

  2. 2.Which day follows 10 Tochtli?

  3. 3.Which of these is NOT one of the twenty day signs?

  4. 4.In a date such as 1 Kiawitl, the number gives:

  5. 5.Why is the Mexika calendar described as an observational science?(Module 1 review)

  6. 6.Buildings oriented to horizon events effectively turn a city into:(Module 2 review)

  7. 7.What does xiuhpowalli count?(Module 1 review)

  8. 8.What do the successive construction stages of the Templo Mayor demonstrate?(Module 2 review)

  9. 9.Why does the count of days run to exactly 260?

  10. 10.The accounts of the Suns frame time as:(Module 1 review)

  11. 11.The codices Borgia, Borbonicus and Telleriano-Remensis are best understood as:

  12. 12.A trecena is:

  13. 13.What does the orientation (azimuth) of a temple record?(Module 2 review)