Patriots sent their acknowledgments to British-born American General Horatio Gates on the Oct. 17, 1777 defeat of the British Army at Saratoga, New York.
Henry Laurens, President of the Continental Congress, wrote that Gates's dispatches to Congress about the "convention" signed by British General John Burgoyne "afforded satisfaction not only to the Representative body, but universally to the good people here, the glorious Intelligence is now extending from City to City diffusing Joy in the heart of every Loyal American to the remotest State in the Union."
Eliphalet Dyer wrote to Gates, "I have the pleasure to Inform you that Congress are not only happy in the Event, but entirely satisfied in your Closing the Convention, at the time, & in the time, & in the manner you did and dare say the Impartial World will not only Justifye but Applaud you therein. The Chance of Warr was too (great to hazzard) dubious to admit of a Delay, the Advantages proposed by Your Enemy, in their terms of surrendry too great, to leave to Chance. The preserving your Army Undiminished, & in spirit & Vigor for future operations, was wise & prudent."
The "Convention" of Saratoga was not an unconditional surrender but a contract stipulating that Burgoyne's 5,871 British soldiers and German mercenaries can return to Europe with the promise they will not fight again return to North America to fight against the American Revolution. This number does not include the wives and children that accompanied many Hessians on their American campaign.
Anticipating that the British command will not honor the Convention, but will return the soldiers to fight the American "rebels," Congress seizes on complaints and statements by Burgoyne to claim that Burgoyne effectively dissolved the Convention. Congress detained the Convention Army or Convention prisoners until the end of the Revolutionary War. By the end of the war, the Convention prisoners still in American custody amount to about 1,500, mostly due to desertion back to the British lines but also due to British soldiers and Hessian mercenaries who settled in America.
Historian Richard Sampson mentioned the 1932 discovery of a letter from British commander Gen. William Howe to Burgoyne. Howe planned to send the German mercenaries back to Europe, but send the British artillery and infantry men to New York City, the command center of British operations in America. Howe rationalized his plan to violate the Convention by remarking that he released approximately 2,200 American prisoners in the winter of 1776-77 but the Americans had yet to release the same number of British prisoners.
Sampson acknowledged that Howe's letter would have justified American suspension of the Convention, if the Americans knew of the letter in 1777. "At the time of the suspension however, Congress had no sound or honest case for their action and the 'stain' on their history remains."
Richard Sampson, Escape in America: The British Convention Prisoners, 1777-1783 (Chippenham, Wiltshire, UK: Picton Pub., 1995), 86.
Sampson to the contrary, Americans had plenty of experience with British disregard of agreements on the treatment of prisoners to know that Burgoyne's men might soon find themselves fighting against the Revolution soon after their release. As New Jersey Governor William Livingston remarked in a pseudonymous essay in Feb. 1778, "Ever since the commencement of the present war, it hath been the cruel and perfidious policy of Britain to consider us as rebels, with whom engagements were not to be observed and whom she might treat with the utmost severity."
Although detained for the remainer of the war, the Convention prisoners socialized with Americans. A Hessian officer and his family were frequent guests of the family of Thomas Jefferson at Monticello. Many a Hessian prisoner married an American lass.