How did various European counties become involved in and impact the outcome of the American Revolution?

The American Revolution had an important alliance with France in 1778, after having their trust by winning the battle in Saratoga. The French not only recognized the new United States but also trade concessions and privileges. One year later in 1779, Spain joined the war against the UK in the side of France. The French decision to join the infant United States in its fight for independence was by far the most important factor in America's winning the Revolutionary War.