Name 2 europeans who contributed to the american cause, and explain their contributions

The Marquis de Lafayette and Friedrich von Steuben are the name of the two Europeans who contributed to the American cause.  

Explanation:

Marquis brought the trained soldiers to Washington during the time of American Revolution when the country needs trained force to lead the American against the Great Britain.

Friedrich von Steuben also played a very important role in the revolutionary war as he trained those (brought by Marquis) troops and shaped the force during the darkest days of the Revolutionary War.

Both played equal and important role on their parts for the America. They served their best effort for the America in the American Revolutionary war.