He served in the campaigns of 1793-94 on the Rhine, after which he seems to have devoted some time to the study of the scientific branches of his profession.

In 1801 he entered the Military School at Berlin, and remained there till 1803.

During his residence there he attracted the notice of General Scharnhorst, then at the head of the establishment; and the patronage of this distinguished officer had immense influence on his future career, and we may gather from his writings that he ever afterwards continued to entertain a high esteem for Scharnhorst.

In the campaign of 1806 he served as Aide-de-camp to Prince Augustus of Prussia; and being wounded and taken prisoner, he was sent into France until the close of that war.

On his return, he was placed on General Scharnhorst's Staff, and employed in the work then going on for the reorganisation of the Army.
He was also at this time selected as military instructor to the late King of Prussia, then Crown Prince.