Who improved discipline in the American army and taught Washington and troops to March?

Baron Friedrich von Steuben, a Prussian military officer, played a crucial role in improving discipline and training in the American army during the Revolutionary War. He joined General George Washington's army at Valley Forge in 1778, where he implemented a rigorous training program that emphasized discipline, proper marching techniques, and battlefield tactics. His efforts significantly enhanced the effectiveness and professionalism of the Continental Army, contributing to their success in the war.