Codex Mexicanus is an oblong-shaped manuscript that contains calendrical and astrological information, some of which is related to the practice of medicine. The manuscript shows signs of wear, probably because this small-format book would almost always have been carried in the pocket of its owner. The first eight pages contain a series of circles within which letters of the Latin alphabet have been inscribed, most likely designating the days of the month. Images of Catholic saints and apostles also are included. The book includes a history of the Aztecs, or Mexica, from the time of their departure, held by some to have occurred in the 11th century, from the mythical or ancient land of Aztlán. It covers the Aztec migration to the Valley of Mexico and continues to the year 1590, with information on the Spanish conquerors and their Christian faith. The book is on amate paper, which was produced from the beaten fibers of Ficus bark and was widely used in the Aztec Empire.