"With the transition from papyrus rolls to the parchment codex is connected a decisive change for the whole area of European book production. It was customary in papyrus rolls to distinguish the ending, which was better protected and in which the author and title were named in the closing script (colophon), by means of larger script or through ornamentation. This usage passed over initially also into the codices. But from roughly AD 500 on, if not already before then, the weight of ornamental layout at the end gradually shifted towards the opening, where the author's portrait and, in the gospels, the canon tables had their natural place anyway. Various factors worked together here with varying rhythm. Thus connected with the colophon was a specifically Christian ornament, the cross as a staurogram, with Rho-bow on the shoulder, plus alpha and omega. It has already shifted to before the text in the miniature codex of John's Gospel. Following the example of the arch-framed canon tables, lists of contents are set under coloured arcades in the sixth century, and from the fifth /sixth century on they also acquire greater emphasis through such formulae as" 'In hoc corpore (codice) continentur. . .' " (Bischoff, Latin Palaeography: Antiquity and Middle Ages  188-89).