Tonalamatl

The tonalamatl [toːnaˈlaːmatɬ] is a divinatory almanac used in central Mexico in the decades, and perhaps centuries, leading up to the Spanish conquest.

The word itself is Nahuatl in origin, meaning "pages of days".

[1][2] The tonalamatl was structured around the sacred 260-day year, the tonalpohualli.

Each page of a tonalamatl represented one trecena, and was adorned with a painting of that trecena's reigning deity and decorated with the 13 day-signs and 13 other glyphs.

These day-signs and glyphs were used to cast horoscopes and discern the future.

The original page 13 of the Codex Borbonicus, showing the 13th trecena of the Aztec sacred calendar. This 13th trecena was under the auspices of the goddess Tlazolteotl , who is shown on the upper left wearing a flayed skin, giving birth to Cinteotl . The 13 day-signs of this trecena, starting with 1 Earthquake, 2 Flint/Knife, 3 Rain, etc., are shown on the bottom row and the left column.