The post-Frederician Prussian army cultivated the glory of the past, but also experienced continuous debates and reforms intending to optimize the army according to the principles of enlightened rationalism. The confrontation with the French revolutionary armies activated intensive discussions, but for the military authorities, the experiences did not call for principal doubts about the suitability of the army. The defeat of 1806, however, did. The following reforms had to handle elementary needs to re-establish the armed forces, but also took the opportunity to create new organisational frameworks and to introduce new principles for recruitment, military justice and officers’ careers. From a quantitative perspective, the important measures converged on the implementation of a general conscription, and from a qualitative perspective, they especially targeted reconciling the educated middle-class with military service. When the break with France in 1813 effaced the previously existing restrictions, the plans resulted not only in an augmentation of the standing army, but in the establishment of complementary military formations of own characters. Their coexistence reflected organisational constraints, as well as different aspects of the previous debates. Although not without improvisations, the authorities were able to increase the armed forces more than sevenfold within about nine months.