Even before the news of Austerlitz reached the ears of Talleyrand and Haugwitz at Vienna, the bearer of Prussia's ultimatum was posing as the friend of France.

On all occasions he wore the cordon of the Legion of Honour; and while the hosts of East and West were in the death-grapple on the Pratzenberg, he strove to convince the French Foreign Minister that the Prussians had entered Hanover only in order to keep the peace in North Germany; that, as Russians had traversed Prussian territory, the French would, of course, be equally free to do so; that Frederick William objected to the descent of any English force in Hanover, which belonged _de facto_ to France; and finally that the Treaty of Potsdam was not a treaty at all, but merely a declaration with the "offer of Prussia's good offices and of mediation, but without any mingling of hostile intentions." Well might Talleyrand write to Napoleon: "I am very satisfied with M.Haugwitz."[46] Napoleon's victory over Prussian diplomacy was therefore won, even before the lightning-stroke of Austerlitz blasted the Third Coalition.
Haugwitz began his conference with the victor at Schoenbrunn on December 13th, by offering Frederick William's congratulations on his triumph at Austerlitz, to which the Emperor replied by a sarcastic query whether, if the result of that battle had been different, he would have spoken at all about the friendship of his master.[47] After thus disconcerting the envoy and upbraiding him with the Treaty of Potsdam, Napoleon unmasked his battery by offering Prussia the Electorate of Hanover in return for the comparatively petty sacrifices of Ansbach to Bavaria, and Cleves and Neufchatel to France.

For the loss of these outlying districts Prussia could buy that long-coveted land.[48] The envoy was dazzled by this glittering offer, and by others that followed.

The conqueror proposed an offensive and defensive alliance, whereby France and Prussia mutually guaranteed their lands along with prospective additions in Germany and Italy; and the Court of Berlin was also to uphold the independence of Turkey.
Such were the terms that Napoleon peremptorily required Haugwitz to sign within a few hours: and the bearer of Prussia's ultimatum on December 15th signed this Treaty of Schoenbrunn, which degraded the would-be arbitress of Europe to her former position of well-fed follower of France.

This was the news which Haugwitz brought back to his astonished King.