It seemed, indeed, as if the time were come for pressing home upon the French; but just at this critical moment Frederick of Prussia intervened in favour of France, and by a threat to invade Bohemia brought Prince Charles back quickly over the Rhine. None the less Wade and his fellows held a council of war and resolved to bring Saxe to action if possible. King George gave his gracious approval to their plan, and on the 31st of July the Allies turned westward and crossed the Scheldt. It still remained to be seen, however, whether Saxe would allow an action to be forced on him; for he lay now, entrenched to the teeth, on the Lys between Menin and Courtrai, which was a pretty clear indication that he would not. At this moment Lord Stair, who had followed the course of operations carefully from England, came forward, like a true pupil of Marlborough, with a new plan of campaign. His advice was that the Allies should turn Saxe's tactics against himself. They should march south to Orchies, between Lille and Tournay, and there encamp, where they would be within reach of half a dozen French fortified towns. The French would not dare to leave the fortresses defenceless; and the garrisons necessary to render them secure would absorb the whole of their force in the field. Then the Allies could send detachments into France and lay Picardy under contribution, or possibly carry out the plan, rejected two years before, of a march to the Seine. The King of Prussia's action only made some bold stroke of the kind the more imperative.[182]