Tonalamatl

{{Short description|Aztec divinatory almanac}}

Image:Codex Borbonicus, p11 trecena13.PNG 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.]]

The tonalamatl {{IPA|nah|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".León-Portilla (1963) 116-20.{{Cite book|title=El tiempo en el tonalamatl|last=Elżbieta.|first=Siarkiewicz|date=1995|publisher=Cátedra de Estudios Ibéricos, Universidad de Varsovia|isbn=9788386483129|oclc=45966622}}

The tonalamatl was structured around the sacred 260-day year, the tonalpohualli. This 260-day year consisted of 20 trecena of 13 days each. 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 best surviving examples of tonalamatl are the Codex Borbonicus and the Codex Borgia.