The 1777 Revolutionary War campaign that helped persuade France to ally with the United States was the Saratoga campaign.
The campaign unfolded from June 14 to October 17, 1777, as British forces attempted to control the strategically important Hudson River valley. Lieutenant General John Burgoyne led the main British army south from Quebec through Lake Champlain and the upper Hudson region.
American victories at the Battle of Bennington and the Battles of Saratoga weakened Burgoyne’s army. He surrendered to General Horatio Gates on October 17, 1777, a major American success that demonstrated the Patriots could defeat a substantial British force.
News of the surrender reached France in December. King Louis XVI then approved negotiations that produced the Franco-American Treaty of Amity and Commerce and Treaty of Alliance, signed on February 6, 1778. The campaign is sometimes confused with the individual Battles of Saratoga, but the campaign includes the wider military operations leading to Burgoyne’s surrender.