Codex

A codex is a form of book consisting of leaves of parchment or paper fastened on one side and folded into gatherings, protected by a binding; the historical predecessor of the modern book. The codex replaced the ancient scroll (volumen) in the first centuries AD and finally displaced it by the 4th–5th centuries, largely owing to the spread of Christianity. Compared with the scroll, the codex had decisive advantages: compactness, capacity, ease of leafing through and quickly finding a needed place, and the ability to write on both sides of a leaf. The codex form determined the very structure of the book — the page, the opening, pagination, the table of contents. The codex as a material object (material, gatherings, binding, script, decoration) is studied by codicology. All the oldest manuscript books of Kyivan Rus' — the Ostromir Gospel, the Izborniks of Sviatoslav — are parchment codices. The term is also used for a particular ancient manuscript (e.g., the Codex Sinaiticus of the Bible).