The Prussians in particular developed their light infantry tactics both in theory and in practice during the early Napoleonic era. There was much disagreement over how much emphasis should be placed on "Jägers", though, and reform was for the most part at the regimental level by more energetic commanders such as Yorck. It was not until the reorganization of the army led by Scharnhorst that the "Jäger" corps was strengthened on a national level. Having suffered crippling defeats at Jena and Lübeck, the Prussian army undertook major reforms, in many ways following the example of the French Revolutionary Army, becoming a nationalized force. Foreign mercenaries were removed, corporal punishment became rare (and was abolished for "Jäger" troops), and promotions were based on merit rather than nobility. New volunteers from a bourgeois background were organized to resist Napoleon's invasion and occupation of Central Europe. Continuing the earlier traditions, in Prussia these "Jäger" were patriotic volunteers, bearing the cost of their weapons and uniforms at their own expense or with the help of contributions from friends and neighbours, and often organizing themselves into clubs and leagues. As one of the early adopters of skirmisher tactics, Yorck became inspector-general of the light infantry in Prussia and oversaw the increase and improvement of the new "Jäger" troops during the years of peace after the Treaty of Tilsit. The most famous of the Prussian "Jäger" were the volunteers of the Lützow Free Corps.