Excerpts from Books and Wikipedia
Disastrous Prussian defeat led to complete reform of the Prussian military, most importantly the establishment of the General Staff system, leading to the dominance of Prussian military in Europe. [Davis: 100 Decisive Battles, p. 282]
"The twin battles of Jena and Auerstedt (older name: Auerstädt) were fought on 14 October 1806 on the plateau west of the river Saale in today's Germany, between the forces of Napoleon I of France and Frederick William III of Prussia. The decisive defeat suffered by the Prussian Army subjugated the Kingdom of Prussia to the French Empire until the Sixth Coalition was formed in 1812.
Several figures integral to the reformation of the Prussian Army participated at Jena–Auerstedt, including Gebhard von Blücher, Carl von Clausewitz, August Neidhardt von Gneisenau, Gerhard von Scharnhorst, and Hermann von Boyen." [Wikipedia]