Answer: He trained the Continental Army at Valley Forge.
Baron von Steuben was a Prussian military officer. He served as Inspector General and a Major General of the Continental army during the American Revolutionary War. He also served as General George Washington's chief of staff in the final years of the war.
He is also credited with teaching the Continental Army the essentials of military drills, tactics and disciplines at Valley Forge. It is said that Steuben wrote the original drills in German, which his secretary then translated into French and a secretary for Washington translated into English every single night. Steuben was very popular among the soldiers. His excellence in teaching was evident during the Battle of Barren Hill and the Battle of Monmouth.