The fundamental document for Diocletian's provincial re-organization is a list of the Dioceses and Provinces of the Roman Empire preserved in a MS. at Verona, which though printed by Maffei in 1742 escaped the notice of historians till Mommsen published it in 1862 in the Abhandlungen of the Berlin Academy, with a commentary in which he easily showed that it is the earliest provincial list we have, earlier than the lists of the Breviarium of Festus, of Polemius Silvius, of the Notitia Galliarum, and the Notitia Dignitatum. He attributed it to A.D. 297, and argued that it represented the new organization of Diocletian which he assumed to have been completed in that year. This conclusion, I believe, is wrong, though, like some other errors of Mommsen, it has been very generally accepted. He admitted, however, that strictly speaking the lower limit of the date of the List is A.D. 342 and the upper A.D. 297. For the present purpose it is enough to point this out; I hope to discuss the question fully in another place.