While Metz exercised this fatal fascination over the protecting army, the First and Second German Armies were striding westwards to envelop both the city and its guardians. Moltke's aim was to hold as many of the French to the neighbourhood of the fortress, while his left wing swung round it on the south. The result was the battle of Colombey on the east of Metz (August 14). It was a stubborn fight, costing the Germans some 5000 men, while the French with smaller losses finally withdrew under the eastern walls of Metz. But that heavy loss meant a great ultimate gain to Germany. The vacillations of Bazaine, whose strategy was far more faulty than that of Napoleon III. had been, together with the delay caused by the defiling of a great part of the army through the narrow streets of Metz, gave the Germans an opportunity such as had not occurred since the year 1805, when Napoleon I. shut up an Austrian army in Ulm. The man who now saw the splendid chance of which Fortune vouchsafed a glimpse, was Lieutenant-General von Alvensleben, Commander of the 3rd corps, whose activity and resource had so largely contributed to the victory of Spicheren-Forbach. Though the orders of his Commander-in-Chief, Prince Frederick Charles, forbade an advance until the situation in front was more fully known, the General heard enough to convince himself that a rapid advance southwards to and over the Moselle might enable him to intercept the French retreat on Verdun, which might now be looked on as certain. Reporting his conviction to his chief as also to the royal headquarters, he struck out with all speed on the 15th, quietly threw a bridge over the river, and sent on his advanced guard as far as Pagny, near Gorze, while all his corps, about 33,000 strong, crossed the river about midnight. Soon after dawn, he pushed on towards Gorze, knowing by this time that the other corps of the Second Army were following him, while the 7th and 8th corps of the First Army were about to cross the river nearly opposite that town. This bold movement, which would have drawn on him sharp censure in case of overthrow, was more than justifiable seeing the discouraged state of the French troops, the supreme need of finding their line of retreat, and the splendid results that must follow on the interception of that retreat. The operations of war must always be attended with risk, and the great commander is he whose knowledge of the principles of strategy enables him quickly to see when the final gain warrants the running of risks, and how they may be met with the least likelihood of disaster.