The tonalamatl in Nahuatl languages pronounced as /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. 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.