le_ of Emperor-maker.[338]
After the death of Constans, (A.D. 350), Magnentius, an officer in the
Gallic army of British birth, set up as Augustus, and was supported
by Gratian, the leader of the Army of Britain, and by his son
Valentinian. Magnentius himself had his capital at Treves, and
for three years reigned over the whole Prefecture of the Gauls. He
professed a special zeal for orthodoxy, and was the first to introduce
burning, as the appropriate punishment for heresy, into the penal code
of Christendom. Meanwhile his colleague Decentius advanced against
Constantius, and was defeated, at Nursa on the Drave, with such awful
slaughter that the old Roman Legions never recovered from the shock.
Henceforward the name signifies a more or less numerous body, more or
less promiscuously armed, such as we find so many of in the 'Notitia.'
Magnentius, in turn, was slain (A.D. 353), and the supreme command in
Britain passed to the new Caesar of the West, Julian "the Apostate."

B. 4.--Under him we first find our island mentioned as one of the
great corn-growing districts of the Empire, on which Gaul was able to
draw to a very large extent for the supply of her garrisons. No fewer
than eight hundred wheat-ships sailed from our shores on this errand;
a number which shows how large an area of the island must have been
brought under cultivation, and how much the country had prospered
during the sixty years of unbroken internal peace which had followed
on the suppression of Allectus.

B. 5.--That peace was now to be broken up. The northern tribes had
by this recovered from the awful chastisement inflicted upon them by
Severus,[339] and, after an interval of 150 years, once more (A.D.
362) appeared south of Hadrian's Wall. Whether as yet they _burst
through_ it is uncertain; for now we find a new confederacy of
barbarians. It is no longer that of Caledonians and Meatae, but of
Picts and Scots. And these last were seafarers. Their home was not in
Britain at all, but in the north of Ireland. In their "skiffs"[340]
they were able to turn the flank of the Roman defences, and may well
have thus introduced their allies from beyond Solway also. Anyhow,
penetrate the united hordes did into the quiet cornfields of Roman
Britain, repeating their raids ever more frequently and extending them
ever more widely, till their spearmen were cut [Errata: to] pieces in
450 at Stamford by the swords of the newly-arrived English.[341]

B. 6.--For the