 At the twin battles of Jena and Auerstedt in 1806 the Prussian – Saxon troops suffered a crushing defeat at the hands of Napoleon.Separated from Prussia, whose state and army leadership withdrew headlong to the east, left without any information concerning Prussian intentions, and with Napoleon's troops about to occupy Saxony, Frederick Augustus had to conclude peace.On 11 December 1806 in Poznań a treaty was signed by authorized representatives of both sides.