anxiety and trouble by Bassianus, the son whom he had brought with him to the north.  The dissoluteness and violence of his character were not changed by the change of scene.  He formed plots and conspiracies against his father’s authority; he raised mutinies in the army; he headed riots; and he was finally detected in a plan for actually assassinating his father.  Severus, when he discovered this last enormity of wickedness, sent for his son to come to his imperial tent.  He laid a naked sword before him, and then, after bitterly reproaching him with his undutiful and ungrateful conduct, he said, “If you wish to kill me, do it now.  Here I stand, old, infirm, and helpless.  You are young and strong, and can do it easily.  I am ready.  Strike the blow.”

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 rallying points in case of an attack, but not for garrisons of any considerable number of men.  Then, between the castles, at smaller intervals still, were turrets, used as watch-towers and posts for sentinels.  Thus the whole line of the wall was every where defended by armed men.  The whole number thus employed in the defense of this extraordinary rampart was said to be ten thousand.  There was a broad, deep, and continuous ditch on the northern side of the wall, to make the impediment still greater for the enemy, and a spacious and well-constructed military road on the southern side, on which troops, stores, wagons, and baggage of every kind could be readily transported along the line, from one end to the other.