The position of the French was one of great advantage. Their left flank leaned on Metz, their right was protected by formidable batteries on the old Roman road and a strong force of cavalry; and so they could await with confidence a frontal attack on the part of a venturesome enemy.
The possibility of continuing the march to Verdun on this day, under the protection of a strong covering rearguard, was, no doubt, out of the question. Supposing the Marshal earnest above everything to effect his retreat, he could do so only by fighting hard for his right of way, and by so freeing himself from the enemy blocking his path.
It is not easy to discern, from a purely military standpoint, why this course was not resorted to. There was the full certainty that only part, and probably only a small part, of the German host could as yet have reached the left side of the Moselle, and when in the course of the day the Divisions detained about Metz arrived, the French had greatly the superiority in strength. But it seems that the Marshal's chief solicitude was lest he should be forced to relinquish his touch of Metz; and he gave almost his whole attention to his left wing. Constantly sending fresh reinforcements thither, he massed the whole Guard Corps and part of the VIth Corps opposite the Bois des Ognons, whence an attack was exceptionally improbable. One is tempted to assume that political reasons alone thus early actuated Bazaine in his resolve to cling to Metz.
Meanwhile the Prussians slowly but surely made their way beyond Flavigny and Vionville, and, assisted by a heavy fire from the artillery, compelled the right wing of the IInd French Corps to retire on Rezonville, a movement which became a flight when the French Generals Bataille and Valazé were killed.
To regain the lost ground the French Guard Cuirassier Regiment threw itself resolutely on the pursuers. But its attack was cut short by the rapid fire of two companies of the 52nd Regiment drawn up in line, which reserved their fire till the enemy were within 250 paces. The horsemen sweeping right and left rushed into the fire of more infantry behind; 243 horses strewed the field, and only the remnants of the regiment wheeled about in swift flight, pursued by two Hussar regiments which had dashed forward from Flavigny. A French battery in front of Rezonville had hardly time to discharge a few shots before it was surrounded. For want of teams the Prussians could not, indeed, carry off the captured guns; but the Commander-in-Chief of the French army, who had himself brought them up, was for several minutes in imminent danger of being taken prisoner.