A codex is an ancient manuscript in book form, consisting of pages made from materials like parchment or papyrus. Unlike scrolls, which were rolled up, codices allowed for easier access to information, making them a significant advancement in the history of writing. They were commonly used in various cultures, including the Roman Empire and Mesoamerica. Codices often contained religious texts, historical records, or literary works. Famous examples include the Codex Mendoza, which documents the history of the Aztecs, and the Codex Sinaiticus, an early manuscript of the Christian Bible. These artifacts provide valuable insights into the cultures and societies that produced them.