In a memorable event , Metternich argued with Napoleon at Napoleon 's 39th birthday celebrations in August 1808 over the increasingly obvious preparations for war on both sides . Soon after , Napoleon refused Metternich 's attendance at the Congress of Erfurt ; Metternich was later glad to hear from Talleyrand that Napoleon 's attempts at the Congress to get Russia to invade Austria had proved unsuccessful . In late 1808 Metternich was recalled to Vienna for five weeks of meetings about the possibility of Austria invading France while Napoleon was on campaign in Spain . His memoranda reported that France was not united behind Napoleon , that Russia was unlikely to want to fight Austria , and that France had few reliable troops that could fight in central Europe . Back in Paris , Metternich was overtly apprehensive about his own safety . When Austria declared war on France , Metternich was indeed arrested in retaliation for the arrest of two French diplomats in Vienna , but the effects of this were minimal . He was allowed to leave France under escort for Austria in late May 1809 . After Napoleon 's capture of Vienna Metternich was conducted to the Austrian capital and exchange there for the French diplomats
Congress of Erfurt
Congress of Erfurt
Klemens von Metternich