they agree in material, do not altogether
agree in plan with those of Bar Hill, and its north face falls in line with
the frontier wall. Rough Castle, near Falkirk, is very much smaller; it is
remarkable for the astonishing [v.04 p.0584] strength of its turf-built and
earthen ramparts and ravelins, and for a remarkable series of defensive
pits, reminiscent of Caesar's _lilia_ at Alesia, plainly intended to break
an enemy's charge, and either provided with stakes to impale the assailant
or covered over with hurdles or the like to deceive him. Besides the dozen
forts on the wall, one or two outposts may have been held at Ardoch and
Abernethy along the natural route which runs by Stirling and Perth to the
lowlands of the east coast. This frontier was reached from the south by two
roads. One, known in medieval times as Dere Street and misnamed Watling
Street by modern antiquaries, ran from Corbridge on the Tyne past
Otterburn, crossed Cheviot near Makendon Camps, and passed by an important
fort at Newstead near Melrose, and another at Inveresk (outside of
Edinburgh), to the eastern end of the wall. The other, starting from
Carlisle, ran to Birrens, a Roman fort near Ecclefechan, and thence, by a
line not yet explored and indeed not at all certain, to Carstairs and the
west end of the wall. This wall was in addition to, and not instead of, the
wall of Hadrian. Both barriers were held together, and the district between
them was regarded as a military area, outside the range of civilization.

The work of Pius brought no long peace. Sixteen years later disorder broke
out in north Britain, apparently in the district between the Cheviots and
the Derbyshire hills, and was repressed with difficulty after four or five
years' fighting. Eighteen or twenty years later (180-185) a new war broke
out with a different issue. The Romans lost everything beyond Cheviot, and
perhaps even more. The government of Commodus, feeble in itself and vexed
by many troubles, could not repair the loss, and the civil wars which soon
raged in Europe (193-197) gave the Caledonians further chance. It was not
till 208 that Septimius Severus, the ablest emperor of his age, could turn
his attention to the island. He came thither in person, invaded Caledonia,
commenced the reconstruction of the wall of Hadrian, rebuilding it from end
to end in stone, and then in the fourth year of his operations died at
York. Amid much that is uncertain and even legendary about his