After the loss of his two bravest generals, Justinian and Nevigastes, the former of whom was slain in the field of battle, the latter in a peaceful but treacherous interview, Constantine fortified himself within the walls of Vienna.

The place was ineffectually attacked seven days; and the Imperial army supported, in a precipitate retreat, the ignominy of purchasing a secure passage from the freebooters and outlaws of the Alps.

[97] Those mountains now separated the dominions of two rival monarchs; and the fortifications of the double frontier were guarded by the troops of the empire, whose arms would have been more usefully employed to maintain the Roman limits against the Barbarians of Germany and Scythia.
[Footnote 94: Claudian, (i.Cons.Stil.l.ii.

250.) It is supposed that the Scots of Ireland invaded, by sea, the whole western coast of Britain: and some slight credit may be given even to Nennius and the Irish traditions, (Carte's Hist.

of England, vol.i.p.