a fourth American threat—General Brooks's VI Corps, which had followed closely the German withdrawal from northeastern Alsace and on 19 March had begun to assault the Siegfried Line on either side of Wissembourg. There, General Petersen's XC Korps was charged with holding the fortifications and denying access to the flatlands along the Rhine. In the Seventh Army's original plan, the attached 3rd Algerian Division on the right wing of the VI Corps along the Rhine was to have been pinched out after it reached the Lauter River at the German frontier. The planners had not reckoned with the aspirations of the French and their First Army commander, General Jean de Lattre. Assured of support from the provisional head of the French state, General Charles de Gaulle, de Lattre was determined to acquire a zone along the Rhine north of the Lauter in order to assure a Rhine crossing site for the final drive into Germany. As the Algerians matched and sometimes exceeded the strides of the American units of the VI Corps and reached the Lauter along a front, de Lattre had no difficulty pressing his ambition on the Sixth Army Group commander, General Devers. Using the 3rd Algerian Division and a combat group from the 5th French Armored Division, again to be attached to the VI Corps, the French (organized as Task Force (Groupement) de Monsabert) were to continue northward some beyond the Lauter River, thereby gaining limited Rhine River frontage inside Germany. The subsequent French advance pushed through the Bienwald, a large forested expanse just north of the Lauter through which bunkers, trenches, and other obstacles of the Siegfried Line were emplaced. In the ensuing clash, elements of the German 257th Volksgrenadier and 905th Infantry Training Divisions were forced to retreat northward in fighting dominated by the forested terrain. The adjustment meant that the Siegfried Line assault by the four American divisions of the VI Corps was to be concentrated in a zone less than wide. Since the German XC Korps had only the remnants of two volksgrenadier divisions and an infantry training division to defend against both Americans and French, a breakthrough of the fortifications was but a matter of time. Yet just as had been the case in the zones of the XXI Corps and the XV Corps, it was less the hard fighting of the VI Corps that would determine when the Siegfried Line would