Before the nineteenth century, success on the battlefield largely depended on the military competence of the sovereign. Duke Frederick William introduced the term "Generalstabsdienst" (General Staff Service) for the Prusso-Brandenburgian army in 1640. While Frederick the Great brought success to the Prussian arms, his successors lacked his talent, so generalship in the Army declined, even though they were assisted by a Quartermaster General Staff of adjutants and engineers established by Frederick the Great. Reformers in the army began to write and lecture on the need to preserve and somehow institutionalize the military talent that Frederick had assembled in his army. They argued that a carefully assembled cadre of talented officer staff could plan logistics and train the Army in peace as well as in war. In the last years of the eighteenth century, it became the practice to assign military experts to assist the generals of Prussia's Army, largely at the instigation of comparatively junior but gifted officers such as Gerhard von Scharnhorst and August von Gneisenau. Nevertheless, such measures were insufficient to overcome the inefficiency of the Army, which was commanded by aged veterans of the campaigns of Frederick the Great, almost half a century earlier.