Of that fact Frederick needed no further evidence than the Convention of Augsburg. His mind was made up. He saw at once that the real object of that Government was, not the protection of German liberties, not the election of the King of Poland, not a decisive war and an honourable peace, but simply a holiday campaign in Flanders. He was utterly exasperated by the vain selfishness of the French policy, while his impatience at its continued tenderness for Saxony mounted to the brim.
"We are on the eve of a new war," he wrote to Louis XV., a fortnight after the loss of Bavaria, "and what I want to know is this: Is Your Majesty going to declare himself for a prince who is giving auxiliaries to the enemies of France, or for the man whose diversion disentangled Alsace; does Your Majesty prefer the artifices of a crafty and secret enemy to the frankness of an honest friend, who has drawn upon himself the whole burden of the war, and whose provinces are now only being ravaged in order to secure the sweets of tranquillity to the subjects who live under French dominion. In a word, I must know if the justice, the honour, the generosity of Your Majesty can consent to leave me without the real assistance which He is bound by treaties to render, and to sacrifice me to a prince who has dethroned Your Majesty's father-in-law, a prince who is sold to the enemies of France, and who is only awaiting the favourable moment to give vent to his hatred and animosity against her."[333]
He gives the French king to understand that for the purposes of the common cause, the siege of Babylon will be as useful as the siege of Tournay;[334] and in despair of producing any effect, he concludes:
"It is simply in the force of his own arms and in the fortune of battles that the King of Prussia puts his greatest trust, in the hope that the goodness of his cause and the valour of his troops will never fail him."[335]
He sees but one remedy for the crisis produced by the loss of Bavaria—the immediate invasion of Hanover by Conti, with the army of the Main.[336]
This advice was a marvel of astuteness. He saw that with the abandonment of France he had nothing further to hope from the war; and that his only resource lay in bringing pressure to bear upon the maritime powers, and extricating himself as best he could. He proceeded to do so, needless to say, without the least compunction. To Frederick, the difference between the open rupture of an alliance and the tacit abandonment of an ally, was one for a casuist and not for a statesman. Events deepened his determination. Decided by the fall of Bavaria, Augustus on the 18th of May had ratified the Treaty of Warsaw arranged in January with Maria Theresa;[337] and on the 4th of June, a combined army of Austrians and Saxons strayed into the "trap" which Frederick had spread for them at Friedbourg.[338] On the 11th of May, Louis XV. had reaped the utterly vain glory of Fontenoy; and shortly afterwards Conti, upon the Main, received orders to detach twenty thousand men for the army of Flanders.[339] The Statesman at Vienna seized the opportunity to unite her armies in Bavaria and Franconia, and Conti, menaced by superior forces, withdrew with his troops beyond the Rhine.[340] There was not a Frenchman left in Germany; and the army of the Empress closed round Frankfort.
At the end of an ironical letter of compliment to the French king, Frederick writes (August 25th):
"It is a pity that in such a fine picture there should be one blot to spoil it a little. I speak of the retreat of the Prince of Conti. It is he who crowns the Grand Duke, and places Your Majesty's allies in a desperate and fatal position."[341]
From that position Frederick was determined to escape; but his success would have been more than doubtful, were it not that at this very moment, a critical conjunction of untoward events softened the obduracy of George II. The French advance in the Low Countries, the clamour of the peace party, and above all, the sweeping success of the gallant Prince Charles Edward, forced King George to listen to terms.[342] If the English troops were to be withdrawn from the Continent, Hanover could not be left at the mercy of Frederick; and only by the suspension of arms in Silesia, could a force be drafted from the Austrian army to relieve the English in the defence of Flanders. A determined effort was made to induce Maria Theresa to consent to a pacification. She would have nothing whatever to do with the traitor of Brandenburg; nor would she listen to any proposal which would involve the withdrawal of a single man from the Silesian frontier.[343] In the meanwhile time pressed; Charles Edward was marching on Edinburgh; and on the 26th of August, the King of England signed the Convention of Hanover, guaranteeing, for himself and his allies, the suspension of the war and the maintenance of Frederick in Silesia.[344]
If Maria Theresa had rejected, three weeks before, the proposals presented to her by her ally of England, she was not more likely to recognise the Convention signed by England upon her behalf. On the very day when Robinson, the English envoy at Vienna, endeavoured to obtain her acceptance of a treaty which snatched her enemy from her grasp, she received the news[345] that the long conflict she had maintained so manfully had ended at last in triumph, and that her husband, the Grand Duke of Tuscany, had been elected Emperor at Frankfort.