Alvensleben's advance was in accordance with Moltke's general plan of operations; but that corps-leader, finding the French to be in force between him and Metz, determined to attack them in order to delay their retreat. The result was the battle of August 16, variously known as Vionville, Rezonville, or Mars-la-Tour--a battle that defies brief description, inasmuch as it represented the effort of the Third, or Brandenburg, corps, with little help at first from others, to hold its ground against the onsets of two French corps. Early in the fight Bazaine galloped up, but he did not bring forward the masses in his rear, probably because he feared to be cut off from Metz. Even so, all through the forenoon, it seemed that the gathering forces of the French must break through the thin lines audaciously thrust into that almost open plain on the flank of their line of march. But Alvensleben and his men held their ground with a dogged will that nothing could shatter. In one sense their audacity saved them. Bazaine for a long time could not believe that a single corps would throw itself against one of the two roads by which his great army was about to retreat. He believed that the northern road might also be in danger, and therefore did not launch at Alvensleben the solid masses that must have swept him back towards the Meuse. At noon four battalions of the German 10th corps struggled up from the south and took their share of the hitherto unequal fight. But the crisis of the fight came a little later. It was marked by one of the most daring and effective strokes ever dealt in modern warfare. At 2 o'clock, when the advance of Canrobert's 6th corps towards Vionville threatened to sweep away the wearied Brandenburgers, six squadrons of the 7th regiment of Cuirassiers with a few Uhlans flung themselves on the new lines of foemen, not to overpower them--that was impossible--but to delay their advance and weaken their impact. Only half of the brave horsemen returned from that ride of death, but they gained their end.