The campaign was initially successful. Burgoyne gained possession of the vital outposts of Fort Ticonderoga (for which he was made a lieutenant-general) and Fort Edward, but, pushing on, decided to break his communications with Quebec, and was eventually hemmed in by a superior force led by American Major General Horatio Gates. Several attempts to break through the enemy lines were repulsed at Saratoga in September and October 1777. His Aide-de-camp Sir Francis Clerke was killed on 15 October. On 17 October 1777, Burgoyne surrendered his entire army, numbering 5,800. This was the greatest victory the American forces had up to that point in the Revolutionary War, and it proved to be the turning point in the war, as France entered into an alliance with the American Patriots.