At Tilsit , Napoleon had made Tsar Alexander of Russia an admirer , but by the time of the Erfurt Congress from September to October 1808 anti-French sentiment at the Russian court was beginning to threaten the newly forged alliance . Napoleon and his foreign minister Jean-Baptiste Nompère de Champagny sought to reaffirm the alliance once more in order to allow Napoleon to settle affairs in Spain , as well as prepare for the looming war with Austria . Working at cross-purposes to Napoleon was his former foreign minister Charles Maurice de Talleyrand-Périgord who had by this time come to the conclusion that Napoleon and his war policies were leading France to destruction , and who secretly advised Alexander to resist Napoleon 's demands
Erfurt Congress
Congress of Erfurt
War of the Fifth Coalition