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.