The Codex Borgia or Codex Yoalli Ehecatl, a Mesoamerican ritual and divinatory manuscript. It is generally believed to have been written before the Spanish conquest of Mexico, somewhere within what is now southern or western Puebla. The codex is made of animal skins folded into 39 sheets. The codex is read from right to left. The Codex Borgia features eighteen pages of an astronomical narrative that shows the yearlong alteration of the rainy and dry season. The Codex Borgia is named after the Italian Cardinal Stefano Borgia, who owned it before it was acquired by the Vatican Library.