 Al-Sufi's included his own observations of Ptolemy's material into this manuscript as well.Most surviving pre-modern manuscripts use the codex format (as in a modern book), which had replaced the scroll by Late Antiquity.Parchment or vellum, as the best type of parchment is known, had also replaced papyrus, which was not nearly so long lived and has survived to the present only in the extremely dry conditions of Egypt, although it was widely used across the Roman world.