Of course Bassianus shrunk from his father's reproaches, and went
away without committing the crime to which he was thus reproachfully
invited; but his character remained unchanged; and this constant
trouble, added to all the other difficulties which Severus
encountered, prevented his accomplishing his object of thoroughly
conquering his northern foes. He made a sort of peace with them,
and retiring south to the line of fortified posts which had been
previously established, he determined to make it a fixed and certain
boundary by building upon it a permanent wall. He put the whole force
of his army upon the work, and in one or two years, as is said,
he completed the structure. It is known in history as the Wall of
Severus; and so solid, substantial, and permanent was the work, that
the traces of it have not entirely disappeared to the present day.

The wall extended across the island, from the mouth of the Tyne, on
the German Ocean, to the Solway Frith--nearly seventy miles. It was
twelve feet high, and eight feet wide. It was faced with substantial
masonry on both sides, the intermediate space being likewise filled
in with stone. When it crossed bays or morasses, piles were driven
to serve as a foundation. Of course, such a wall as this, by itself,
would be no defense. It was to be garrisoned by soldiers, being
intended, in fact, only as a means to enable a smaller number of
troops than would otherwise be necessary to guard the line. For these
soldiers there were built great fortresses at intervals along the
wall, wherever a situation was found favorable for such structures.
These were called _stations_. The stations were occupied by garrisons
of troops, and small towns of artificers and laborers soon sprung up
around them. Between the stations, at smaller intervals, were other
smaller fortresses called castles, intended as places of defense, and