Codex Sierra
Image:Codex Sierra part.jpg|300px|thumb|right|An elaborate year sign in the Codex Sierra. The text begins: Inaxca xihuitli yeytzontli ynpa castolpoali xihuitli ynpa yepohualli omeyxihuitli 1563. ¶ cuiya qhuiyo The Christian year is written in Nahuatl, and the indigenous year in Mixtec.
The Codex Sierra is a colonial Mesoamerican account book from Santa Catalina Texupa, covering the years from 1550 to 1564. It uses both alphabetic and Mesoamerican [writing systems|pictorial] modes of writing. Though Texupa is a Mixtec and Chocho community, the text is written in Nahuatl, albeit with some Mixtec words. The pictorial portion likewise uses Mixtec conventions, such as the "A-O" year sign.