In the Jena and Friedland campaigns, the Hapsburgs played the part of the sulking Achilles, and met their natural reward in 1809.

The war of 1812 marshalled both Austria and Prussia as vassal States in Napoleon's crusade against Russia.

But it also brought salvation, and Napoleon's fateful obstinacy during the negotiations at Prague virtually compelled his own father-in-law to draw the sword against him.
Ostensibly, the points at issue were finally narrowed down to the control of the Confederation of the Rhine, the ownership of North Germany, and a few smaller points.

But really there was a deeper cause, the character of Napoleon.
The vindictiveness with which he had trampled on his foes, his almost superhuman lust of domination, and the halting way in which he met all overtures for a compromise--this it was that drove the Hapsburgs into an alliance with their traditional foes.

His conduct may be explained on diverse grounds, as springing from the vendetta instincts of his race, or from his still viewing events through the distorting medium of the Continental System, or from his ingrained conviction that, at bottom, rulers are influenced only by intimidation.
In any case, he had now succeeded in bringing about the very thing which Charles James Fox had declared to be impossible.