The Aubin Tonalamatl is a pictorial calendar from the region of Puebla-Tlaxcala, Mexico, and rooted in the Nahua (Aztec) culture. The word "tonalamatl" is made up of two Nahuatl words, "tonalli" meaning day, and "amatl" referring to the paper substrate that this codex is written on.
It is an extremely rare divinatory ritual almanac or handbook painted on maguey bark paper, and originally consisted of 20 pages although 2 have been lost.
Its date of composition is unknown. It shows no elements of European influence, so it is likely to be from the pre-Conquest period, but it may have been copied during the early years of the Spanish Conquest (1519–1523).
Each square is one day, grouped into twenty 13-day periods called trecenas, which makes up the complete 260 day Mesoamerican ritual calendar. Each square records omens associated with that day, and which also formed the basis for their unique natal astrology system.
Read the fascinating story about how the codex was smuggled from the Blbiothèque Nationale de France in Paris back to Mexico, where it remains today, after having been sold and resold by collectors since the conquest of Mexico by the Spanish.