The idea with which Frederick began the Silesian adventure was at length realised. He had, as he anticipated, stirred up general confusion, amid which the strong man who knew his own mind could hardly fail to carry off some spoils. To France, as the moving spirit, he was all gratitude and devotion. But his real design henceforward was to leave his confederates to subdue Austria, while he himself devoted all his powers to grasping what Prussia could hope to retain. What he gained from Belleisle’s work was made manifest in the summer and autumn of 1741. While the Bavarians and French were advancing in triumph down the Danube towards Vienna, the Austrians could take no thought for Silesia. Frederick, therefore, had leisure to train his cavalry and consolidate his conquest. He treacherously destroyed the municipal independence of Breslau, which he had bound himself to preserve, but did little actual fighting. Neisse, protected by Neipperg’s army, seemed still too strong to be attacked.
Meanwhile the extreme peril of Maria Theresa’s throne forced the Queen to make trial of desperate remedies. By throwing herself upon the generosity of the Hungarians, the traditional rebels against her House, she more than doubled the force at her disposal. Her endeavour to purchase France was futile, but a hint from Frederick was now enough to inaugurate negotiations with Prussia. Early in October these issued in the famous convention of Klein Schnellendorf. In deep secrecy, for Fleury had written that the King of Prussia was false in everything, even in his caresses, and the French ambassador kept a watchful eye upon his movements, Frederick met Neipperg at a castle in the neighbourhood of Neisse. Each was accompanied by one companion, while the English ambassador, Lord Hyndford, who had arranged the interview, acted as clerk and witness. There Frederick, who had just written to Belleisle a letter full of encouragement, sold his allies for his own profit. It was agreed that after a sham siege of Neisse the Austrians should evacuate Silesia, and that Prussia should become neutral in fact though not in show. To Neipperg, whose army would now be free to act against the French in Bohemia, Frederick gave wise counsel for the campaign. “Unite all your troops, then strike home before they can strike you.” If the Austrians should succeed, Frederick might join them; if not, he would be compelled to look to himself. To deceive the French, the English ambassador was to report him as deaf to all propositions. If any word of the convention got abroad, the King declared he would deny all and regard all as void.