It was the spirit which animated the Roman legions, and the discipline to which they were inured that gave them their irresistible strength.  When we remember that they had not our firearms, we can but be surprised at their efficiency, especially in taking strongly fortified cities.  Jerusalem was defended by a triple wall, the most elaborate fortifications, and twenty-four thousand soldiers, besides the aid received from the citizens; and yet it fell in little more than four months before an army of eighty thousand under Titus.  How great must have been the military science that could reduce a place of such strength, in so short a time, without the aid of other artillery than the ancient catapult and battering-ram!  Whether the military science of the Romans was superior or inferior to our own, no one can question that it was as perfect as it could be, lacking any knowledge of gunpowder; we surpass them only in the application of this great invention, especially in artillery.  There can be no doubt that a Roman army was superior to a feudal army in the brightest days of chivalry.  The world has produced no generals greater than Caesar, Pompey, Sulla, and Marius.  No armies ever won greater victories over superior numbers than the Roman, and no armies of their size ever retained in submission so vast an empire, and for so long a time.  At no period in the history of the Roman empire were the armies so large as those sustained by France in time of peace.  Two hundred thousand legionaries, and as many more auxiliaries, controlled diverse nations and powerful monarchies.  The single province of Syria once boasted of a military force equal in the number of soldiers to that wielded by the Emperor Tiberius.  Twenty-five Roman legions made the conquest of the world, and retained that conquest for five hundred years.  The self-sustained energy of Caesar in Gaul puts to the blush the efforts of all modern generals, unless we except Frederic II., Marlborough, Napoleon, Wellington, Grant, Sherman, and a few other great geniuses whom warlike crises have developed; nor is there a better text-book on the art of war than that furnished by Caesar himself in his Commentaries.  The great victories of the Romans over barbarians, over Gauls, over Carthaginians, over Greeks, over Syrians, over Persians, were not the result of a short-lived enthusiasm, like those of Attila and Tamerlane, but extended over a thousand years.

The Romans were essentially military in all their tastes and habits.  Luxurious senators and nobles showed the greatest courage and skill in the most difficult campaigns.  Antony, Caesar, Pompey, and Lucullus at home were enervated and self-indulgent, but at the head of their legions they were capable of any privation and fatigue.