After several skirmishes the Detachment approached the place, but when on the 22nd preparations were being made to storm it from three sides, it was found that the enemy had already evacuated it. At the same time orders arrived from the supreme Headquarter, instructing the Grand Duke to fall back at once on Beaugency to join the right wing of the IInd Army, which it was necessary should immediately be reinforced in view of the superior strength of the enemy. "The force now massing before Orleans is to postpone all hostilities until the arrival of the Detachment. The slight opposition offered by the French on the Eure and Huisne sufficiently shows that no serious danger threatens on that side; the enemy in that quarter need only be kept under observation by cavalry." The Detachment was not to be permitted even a single rest day, and its march was to be conducted with the utmost speed. On the 23rd, the Divisions had closed up on their respective heads, and the Grand Duke on the 24th moved on Chateaudun and Vendome; but the Bavarian Corps only got as far as Vibraye, while the two Prussian Divisions withdrew from the difficult country of the Perche, and the cavalry found the whole line of the Loir held by the enemy. In fact, the French had sent a brigade of the troops massed behind the forest of Marchenoir by railway to Vendome, expressly to protect the Government at Tours, while General de Sonis had advanced with the rest of the XVIIth Corps on Brou. Here on the 25th his advance met an ammunition column and bridge-train of the Bavarian Corps. At first only the 10th Cavalry Brigade could engage the enemy, but when presently two companies and eight guns had occupied the bridge over the Loir at Yevres, the waggons were got through Brou in safety, and the enemy could not enter that place till the cavalry had continued its march. The Bavarian Corps was meanwhile advancing on Mondoubleau and St. Calais, not certainly the shortest route to Beaugency, but, on the contrary, on the direct road to Tours. The two Divisions only reached the vicinity of Vibraye and Authon. The appearance of a hostile force at Brou was deemed of sufficient importance to justify a detour by that place, postponing for the moment the prescribed march on the Loire. But when the 22nd Division approached Brou on the 26th, it found that the enemy had already retired during the night. The Government at Tours had ordered the whole of the XVIIth Corps to concentrate at Vendome for their protection. But when the German cavalry made its appearance at Cloyes and Freteval, General Sonis considered that he could not pursue his march further along the Loir, and made a detour by Marchenoir. But two night-marches so shattered the levies for the first time collected in mass that whole swarms of stragglers wandered about the neighbourhood all day and could only with difficulty be re-assembled at Beaugency.