In resting his plan upon a defence of the eastern pivot of the retreat and the recoil, Joffre was accepting an accomplished fact. The great attack upon the Couronné of Nancy began on the evening of September 4, thirty-six hours before the Allied offensive. It may be supposed, therefore, that the German Staff had decided to get the Bavarian Army into a position in which it could co-operate effectively with the Imperial Crown Prince when he came up level on the west. Heeringen’s push from the St. Dié region toward Epinal, and the attack on the Mortagne, were probably intended to hide this design, and to pin down Dubail’s forces. The promptitude with which Heeringen was sent off to the Aisne, on the night of September 6, that is, as soon as the danger of Kluck’s position was realised, is significant. In itself, the presence of the Kaiser during the Bavarian attack on the Grand Couronné proves nothing. His ceremonial entry into Nancy would have grievously hurt French pride; but the sacrifice of the city had always been contemplated, Toul being the real redoubt of the Moselle defences. The prize was to be larger; the prestige of three royal personages was to be satisfied. The Crown Princes of Prussia and Bavaria, ingeniously linked, had been so directed that in the crisis they had the whole Verdun–Toul system between them, and apparently at their mercy. The assault of the Amezule defile and Mount Amance was reciprocal to the adventure which Sarrail arrested 50 miles farther west.