Mommsen’s account of the Wall of Pius between Forth and Clyde and of the Roman occupation of Scotland also needs modification. Statistics of coins found in Scotland (printed in _Antonine Wall Report_, 1899, pp. 158 foll., confirmed by all later finds) show that the Romans had retired south of Cheviot by about A.D. 180, and never reoccupied the positions thus lost. The mass of inscriptions, to which Mommsen alludes, also contains nothing later than the reign of Marcus. It becomes, therefore, impossible to connect the Wall of Pius with the literary evidence relating to wall-building by Severus. That evidence must belong to the Tyne and Solway. The length which it assigns to the wall, cxxxii. miles, suits the southern line best. The numeral in any case needs emendation, but it is as easy to read lxxxii. as xxxii., and 82 Roman miles fit closer to the length of the southern line (73-1/2 English miles) than do 32 Roman miles to the 36-1/2 English miles of the northern wall. Our knowledge of the northern wall itself and of forts either north of it, like Ardoch, or south, like Lyne and Newstead, has been much widened by excavation, but the gain has been rather to the archaeologist than to the pure historian. In the later history of north Britain the chief recent addition has been evidence of a serious rising about A.D. 158, which perhaps covered all the land of the Brigantes from Derbyshire to Dumfriesshire. Inscriptions found at Birrens, at Netherby between Birrens and Carlisle, at Newcastle-on-Tyne, and at Brough in north Derbyshire, mention a governor Iulius Verus as then specially active, and special reinforcements as then arriving from Germany (_Proc. Soc. Antiq. Scot._ xxxviii. 454). It is natural to connect these with the words of Pausanias (cited on p. 188, note 2), and the connection had the approval of Mommsen. For the division of the province into two by Severus see Domaszewski, _Rangordnung_, p. 173. The boundary between the two provinces is unknown; perhaps a line from the Humber to the Mersey is not altogether improbable. Nor is there evidence to show how long the division lasted.