The American victory at Saratoga in 1777 was so decisive that it convinced France to enter the war — and transformed a colonial rebellion into a global conflict.
British General John Burgoyne launched his 1777 campaign with an ambitious plan: march south from Canada, capture the Hudson River Valley, and split New England from the rest of the colonies. What he got instead was one of history's most consequential military defeats.
At the First Battle of Freeman's Farm on September 19, American sharpshooters picked apart British formations from the treeline while Burgoyne's forces advanced in open order. The British technically held the field but suffered 600 casualties — a rate they could not sustain.
Burgoyne waited three weeks for reinforcements from General Clinton in New York that never arrived. Meanwhile, American militia from across New England poured in, swelling Gates's army to over 11,000 men. Burgoyne was running out of time and supplies.
At the Second Battle on October 7, Benedict Arnold — who had been relieved of command after a furious argument with General Gates — rode onto the battlefield anyway, still technically under suspension. Leading troops by sheer force of personality, he was shot through the leg but helped shatter the British lines.
On October 17, 1777, Burgoyne surrendered his entire army of nearly 6,000 soldiers — an almost unheard-of catastrophe for a British force. The soldiers of the 'Convention Army' became prisoners of war for the rest of the conflict.
News of Saratoga reached Paris within weeks and tipped the scales. King Louis XVI had been waiting for proof that America could actually win. He had his proof. France formally entered the war as an American ally in February 1778, bringing its navy, army, and treasury to bear against Britain.