Friedrich Wilhelm von Steuben
Steuben joined the Prussian army when he was 16.  He learned that the Prussian army was a good army because it was very disciplined.  He became a lieutenant.  He fought in the Seven Years War.  He became a captain.  He worked for General Johann von Mayer.  In 1762, he was aide-de-camp to Frederick the Great.  Steuben was in the army 17 years.