C. It persuaded France and Spain to become allies. The Battle of Saratoga in 1777 is considered a turning point in the American Revolutionary War. Before the battle, the continental army rarely engaged in open battles with the British, instead using guerrilla tactics and secret ambushes in skirmish fights in the beginning of the war. The continental army needed foreign aid if it wanted to win the war against the much more professionally organized British army. France and Spain were rivals with Britain, but needed proof that the colonists may take on the British army in an open battle if it wanted to join the war on the colonists' side. The continental army had the opportunity to do so at the Battle of Saratoga in upstate New York, and successfully drove back British forces from Canada in open combat, allowing the French and Spanish to join the war against Britain.