Codex had emerged as the book of the Christians even as the Roman Empire was about to disintegrate. Codex replaced the scrolls. Codex book production was a technology that allowed a shift from a focus on the oracy of the agora to one on scribes, writing materials and the written word. Portability was sacrificed in such a development, hence the library as conceived today. There was as yet no such technology as the printing press, which reduced the cost of production to an incredible degree. The printing press was an astonishing invention. Where a book may have been calculated at perhaps $400 to produce, a printed version was the equivalent of $1. This was still far in the future.