"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of the gallant Prince Charles Edward, forced King George to listen to terms.[342] If the English troops were to be withdrawn from the Continent, Hanover could not be left at the mercy of Frederick; and only by the suspension of arms in Silesia, could a force be drafted from the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. This election took place on the 3rd of September. It shattered once for all the diplomatic combinations which the labour and enthusiasm of d'Argenson had endeavoured singly to sustain. To crown the catastrophe, he was abandoned by the man to whom everything had been sacrificed; for the King of Poland, a few days before, declared in favour of the Austrian candidate.[346] At the very moment of this palpable collapse of French influence in Germany, the air became heavy with rumours of the withdrawal of Frederick from the French alliance. It is no easy matter to determine d'Argenson's real share in these events; but it seems clear that whatever tone be assumed in regard to it, it cannot be that of harsh contempt.