A codex (Latin for block of wood, book; plural codices) is a book in the format used for modern books, with separate pages normally bound together and given a cover. Although the modern book is technically a codex, the term is used only for manuscripts. The codex was a Roman invention that replaced the scroll, which was the first book form in all Eurasian cultures.
While non-Christian traditions such as Judaism used scrolls, early Christians used codices before it became popular. Christian scholars seemed to have used codices in order to distinguish their writings from Jewish scholarly works due to controversy and dispute particularly regarding the Old Testament and other theological writings. By the fifth century, the codex became the primary writing medium for a general use. While the practical advantages of the codex format contributed to its increasing use, the rise of Christianity in the Roman Empire may have helped spread its popularity.
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