Under these circumstances, it was evidently impossible for Frederick to retain Silesia unless he could again rally France and other powers to his aid. It was always easy to rouse France against England, its hereditary foe. Thus influenced, Frederick, early in the spring of 1744, entered into a new alliance with France and the Emperor Charles Albert against Maria Theresa. The two marriages which he had so adroitly consummated constrained330 Russia and Sweden to neutrality. While France, by the new treaty, was engaged to assail with the utmost energy, under the leadership of Louis XV. himself, the triumphant Austrian columns upon the Rhine, Frederick, at the head of one hundred thousand troops, was to drive the Austrians out of Bohemia, and reseat Charles Albert upon his hereditary throne. For this service Frederick was to receive from the Bohemian king three important principalities, with their central fortresses near upon the borders of Silesia.